All Calculators

• 3-Phase Power Calculator

  Calculate three-phase power in kW, kVA and kVAR from voltage, current and power factor, or the current drawn by a three-phase load.

• 401(k) Calculator

  Project a 401(k) balance, and find out exactly how much employer match is being left on the table — the one guaranteed…

• 50/30/20 Budget Calculator

  Your actual split against the rule — including the income the rule would need to work for your fixed costs, when it…

• A1C Calculator

  Convert HbA1c to estimated average glucose and back, in % or mmol/mol and mg/dL or mmol/L — with the wide scatter behind…

• Absolute Value Calculator

  Find the absolute value of a number, the distance between two numbers, or solve an absolute value equation for its two answers.

• Acceleration Calculator

  Calculate acceleration from a change in speed over time, over a distance, or from force and mass, in m/s², ft/s² and g.

• Acres to Square Feet Calculator

  Convert acres to square feet exactly, with square metres, hectares, square yards and the side of an equal square plot.

• Add Days Calculator

  Add or subtract any number of days from a date to find the resulting date and weekday, with the weekday-only equivalent and…

• Age Calculator

  Find exact age in years, months and days from a date of birth, with totals in months, weeks, days and hours and…

• Aggregate Calculator

  Convert an amount of gravel, sand, stone or other aggregate between cubic yards, US tons, cubic metres and tonnes using its typical…

• Alcohol Units Calculator

  UK units, grams of alcohol and US and Australian standard drinks for any drink — because a 'unit' means something different in…

• Amortization Calculator

  See a loan broken down year by year — how much of each payment is interest, when the balance is half repaid,…

• Annuity Calculator

  What a pension pot buys as guaranteed income, how long you must live to get it back, and why the annuity rate…

• ANOVA Calculator

  Run a one-way ANOVA to compare the means of three or more groups, with the F statistic, p-value, ANOVA table and eta…

• Appliance Energy Calculator

  Yearly energy use, running cost and CO2 for common household appliances or your own, including standby power.

• APR Calculator

  Work out the true APR once fees are folded in — and the three things APR leaves out, including what compounding actually…

• APY Calculator

  Turn a savings rate into its APY, compare two accounts that compound differently, or work back from an advertised APY to the…

• Aquarium Gravel Calculator

  Work out how many pounds or kilograms of aquarium gravel or sand you need for your tank's footprint and depth, flat or…

• Aquarium Stocking Calculator

  Check the stocking level of a mixed community aquarium as a percentage, with waste-weighted fish sizes and a filter turnover check.

• Aquarium Substrate Calculator

  Work out litres of planted-tank substrate for a sloped aquascape with an optional nutrient base layer, and how many bags of aquasoil…

• Area Calculator

  Find the area of a rectangle, triangle, circle, trapezoid, parallelogram, ellipse, sector or regular polygon — one page for every common shape.

• Area Converter

  Convert areas between square millimetres, metres and kilometres, hectares, square inches, feet, yards and miles, and acres.

• Arithmetic Sequence Calculator

  Find any term of an arithmetic sequence, the sum of its first n terms, or work backwards from two known terms to…

• ARV Calculator

  Estimate a property's after repair value from comparable sales per square foot, with the value range and the maximum offer by the…

• Aspect Ratio Calculator

  Find the aspect ratio of any width and height, such as 1920 × 1080 = 16:9, or resize to a new width…

• Asphalt Millings Calculator

  Work out the tons of recycled asphalt millings for a driveway or lot from the compacted depth, and compare the cost with…

• Asphalt Tonnage Calculator

  Work out how many tons of hot-mix asphalt you need from the area and compacted thickness, with the spread rate, truckloads and…

• Attendance Calculator

  Work out your attendance percentage, how many classes you must attend to reach the minimum, or how many you can still miss.

• Auto Loan Calculator

  Work out a car loan payment including sales tax, fees and a trade-in — and see how long you would owe more…

• Average Calculator

  Find the mean, median, mode and range of a list of numbers, and see which average actually represents your data.

• Baby Weight Percentile Calculator

  Where your baby's weight sits on the WHO growth standards, from birth to two years, by exact day of age — with…

• BAC Calculator

  Estimate blood alcohol with the Widmark formula, the realistic range around it, and how long until it reaches zero — never whether…

• Baking Pan Conversion Calculator

  Compare two cake tins or baking pans — round, square or rectangular — by area, and scale the recipe so the batter…

• Bandwidth Calculator

  The connection speed needed to move data in a set time, or the monthly data and average bandwidth a website uses.

• Barbell Plate Calculator

  Find which plates to load on each side of the bar for any target weight, in kg or lb, with the bar,…

• Barista FIRE Calculator

  Work out your Barista FIRE number, the savings that let part-time work cover the rest of your spending, and how long it…

• Barndominium Cost Calculator

  Estimate the cost to build a barndominium from the living area, shop space, finish level and site work, with the total and…

• Baseboard Calculator

  How many lengths of baseboard or skirting to buy for a room, from its perimeter less the doors, with corners and finishing…

• Basis Points Calculator

  Convert basis points to percentage points, apply a rate change in bps, or find the gap between two rates, with the yearly…

• Basketball Efficiency Calculator

  A basketball player's efficiency rating (EFF) from points, rebounds, assists, steals, blocks, missed shots and turnovers, with true shooting percentage.

• Bathroom Remodel Calculator

  Estimate the cost of a bathroom remodel from its size and finish level, with plumbing changes, a contingency and the typical labour…

• Batting Average Calculator

  A baseball or softball batting average from hits and at-bats, how it rates, and the hits needed to reach a target average.

• Bench Press Standards Calculator

  See how your bench press compares with strength standards for your bodyweight and sex, from Beginner to Elite, and what the next…

• Bill Split Calculator

  Split a restaurant bill with tax and tip between any number of people, with the tip on the pre-tax or after-tax amount…

• Billable Hours Calculator

  Billable hours in a year from your working week, weeks worked and non-billable time, with utilisation and the revenue at your hourly…

• Binary Calculator

  Add, subtract, multiply and divide binary numbers, apply bitwise operations and shifts, and convert to decimal and hex.

• Binomial Distribution Calculator

  Find binomial probabilities — exactly k successes, at most, at least, fewer or more — for n trials with a fixed chance…

• Birthday Calculator

  Count down to your next birthday, find the weekday it falls on and the day you were born, plus your star sign…

• Birthday Paradox Calculator

  The chance that two people in a group share a birthday, how many people give any target probability, and the chance someone…

• Blacktop Calculator

  Estimate the cost of a blacktop driveway or pad, adding the asphalt, the stone base and labour, with the total and the…

• Block Calculator

  Concrete blocks for a wall from its area less openings, counted with their mortar joints, with courses and total weight — UK…

• Block Wall Calculator

  Lay out a concrete block wall course by course: courses, full and half blocks for running bond, cap blocks, mortar bags and…

• Blood Pressure Calculator

  Classify a blood pressure reading, or the average of three, under both the US and European guidelines — which disagree about where…

• Blood Sugar Converter

  Convert blood glucose between mg/dL and mmol/L, then read it against the right thresholds for fasting, after a meal or a random…

• BMI Calculator

  Body mass index with the healthy weight range for your height, the lower Asian thresholds, and the height bias built into the…

• BMI Percentile Calculator for Children

  A child's BMI placed on the WHO percentile for age and sex, from 2 to 19 years, with the WHO weight categories…

• BMI Prime Calculator

  BMI as a fraction of the healthy upper limit, so 1.0 is the edge — a rescaling that adds legibility and, deliberately,…

• BMR Calculator

  Resting metabolic rate from three different equations, with the spread between them — because every one of them is a population regression,…

• Body Fat Calculator

  Body fat from tape measurements, with how much a centimetre of waist error moves the answer — usually more than a fortnight…

• Body Recomposition Calculator

  Find your goal weight at a target body fat percentage, how much fat to lose and lean mass to keep or gain,…

• Body Surface Area Calculator

  Body surface area by four formulas, with the scaling test that separates the two that are dimensionally exact from the two that…

• Bond Yield Calculator

  Coupon rate, current yield and yield to maturity side by side — and what the bond returns if you spend the coupons…

• Boolean Algebra Calculator

  Simplify a Boolean expression to a minimal sum of products and product of sums using Quine–McCluskey, with optional don't-care conditions.

• Boolean Expression Calculator

  Build the truth table of a Boolean expression, list its minterms and maxterms with canonical SOP and POS, and test whether two…

• Boolean Logic Calculator

  Find the output of AND, OR, NOT, NAND, NOR, XOR and XNOR logic gates for your inputs, with the gate's truth table,…

• Bowling Score Calculator

  Score a ten-pin bowling game from standard notation — strikes, spares and misses — frame by frame, with the total and counts…

• Boyle’s Law Calculator

  Solve Boyle's law, P1V1 = P2V2, for any pressure or volume of a gas at constant temperature, with the change explained step…

• Bread Hydration Calculator

  Dough hydration from flour and water, or the water needed for a target hydration, with sourdough starter included and salt at 2%.

• Break-Even Calculator

  Units and sales needed to cover fixed costs, the contribution margin, the sales for a target profit and your margin of safety.

• Brick Calculator

  Bricks for a wall from its area less openings, counting the mortar joint each brick includes — the detail that turns 72…

• Budget Calculator

  A monthly budget that counts the bills that are not monthly — which is the line most budgets leave out and the…

• Bulk Discount Calculator

  Total cost and average unit price under up to three quantity-discount tiers, all-units or incremental, and whether buying more would cost less.

• Business Days Calculator

  Count the business days between two dates, excluding weekends and any holidays you list, with the calendar breakdown and working hours.

• Butter Conversion Calculator

  Convert butter between sticks, cups, tablespoons, teaspoons, grams, ounces, pounds and 250 g blocks.

• Caffeine Calculator

  Add up a day's caffeine from coffee, tea, cola and energy drinks, check it against the advised limit, and see how much…

• Cake Pricing Calculator

  Price a custom cake from ingredients, supplies, hours and your hourly rate, adding overhead and profit, with the price per serving.

• Calorie Calculator

  Daily calories for a goal, with the plateau built in — because the 3,500-calorie rule draws a straight line and weight loss…

• Calorie Deficit Calculator

  Work backwards from a target weight and a date to the intake that actually reaches it — and find out when the…

• Calories Burned Calculator

  Estimate calories burned for running, walking, cycling, swimming, gym and sport from your weight and time, using MET values.

• Candle Wax Calculator

  Work out how much wax and fragrance oil to melt for a batch of container candles from the jar capacity, fill level…

• Capacitance Calculator

  Calculate a capacitor's charge and stored energy, its capacitance from charge, the RC time constant, or capacitors combined in series and parallel.

• Car Affordability Calculator

  What a car really costs to own, and how many months you spend owing more than it is worth — the two…

• Car Scrap Value Calculator

  Estimate what a scrap yard will pay for your car from its curb weight and the price per ton, with the catalytic…

• Carb Calculator

  Carbohydrate targets by training load, plus how much glycogen you can actually store — because carb loading has a ceiling.

• Carpet Calculator

  How much carpet to buy from a 4 m, 5 m or 12 ft roll, laying it the way that wastes least,…

• Carpet Cleaning Cost Calculator

  Estimate carpet cleaning costs from the number and size of rooms, price per square foot, stairs and pet treatment, with a minimum…

• Cash Flow Calculator

  Monthly net cash flow, the closing balance after a number of months, and your cash runway if more money is going out…

• Cat Age Calculator

  Your cat's age in human years from the chart feline vets use, with its life stage, from kitten to senior.

• CD Calculator

  Work out what a certificate of deposit pays at maturity, what the lock-up is actually buying over easy access, and what breaking…

• Ceiling Tiles Calculator

  Work out the tiles and grid for a drop ceiling: 2×2 or 2×4 tiles, main tees, cross tees, wall angle and hanger…

• Celsius to Fahrenheit Calculator

  Convert degrees Celsius to Fahrenheit with the formula shown step by step, plus kelvin and a quick mental estimate.

• CGPA to Percentage Calculator

  Convert a CGPA to a percentage with the CBSE × 9.5 rule, the VTU formula, a plain ten-point conversion or the four-point…

• Chapter 13 Bankruptcy Calculator

  Estimate a Chapter 13 plan payment from disposable income, priority debts, secured arrears and assets, with what unsecured creditors may receive.

• Character Counter

  Count characters with and without spaces, letters, digits and punctuation, bytes and SMS messages, and check text against post and SEO limits.

• Charles’s Law Calculator

  Solve Charles's law, V1/T1 = V2/T2, for the volume or temperature of a gas at constant pressure, converting °C and °F to…

• Chi-Square Calculator

  Run a chi-square goodness-of-fit test or a test of independence on a contingency table, with expected counts, p-value and Cramér's V.

• Child Height Predictor

  Predict a child's adult height from the parents' heights using the mid-parental method, with the range most children of those parents actually…

• Cholesterol Ratio Calculator

  Total-to-HDL ratio with non-HDL cholesterol beside it, LDL estimated where valid, in mg/dL or mmol/L — and the one ratio that changes…

• Christmas Tree Light Calculator

  Work out how many Christmas tree lights and strings your tree needs for the look you want, plus the wattage and season's…

• Churn Rate Calculator

  Customer churn and retention rates for a month or year, the annual rate a monthly churn compounds to, and the average customer…

• Cinder Block Wall Calculator

  Count the cinder blocks for a wall, with openings and waste, and get the total weight, pallets to order and the cost…

• Circle Calculator

  Enter any one of radius, diameter, circumference or area and get the other three, plus the exact value in terms of pi.

• Class Rank Percentile Calculator

  Turn a class rank such as 15th of 300 into a top percentage and percentile, or find the rank you need for…

• Closing Costs Calculator

  The cash you actually need on completion day — deposit plus fees, with prepaid tax and insurance separated out from the fees…

• cm to Inches Calculator

  Convert centimetres to inches, with feet and inches and the nearest sixteenth of an inch as on a tape measure.

• Cocktail Ratio Calculator

  Scale a margarita, daiquiri, negroni, old fashioned, cosmopolitan or whiskey sour to any number of drinks, with dilution, strength and bottles.

• Coefficient of Variation Calculator

  Find the coefficient of variation — the standard deviation as a percentage of the mean — from a data list or a…

• Coffee Ratio Calculator

  Coffee to water ratio for pour-over, French press, drip, AeroPress, cold brew and espresso, with grams, tablespoons, grind and brew time.

• COGS Calculator

  Cost of goods sold from beginning inventory, purchases, direct costs and ending inventory, with gross margin and inventory turnover.

• Coin Flip Simulator

  Flip a virtual coin once or up to 10,000 times, with the heads and tails count, the longest streak and how likely…

• College Admission Calculator

  Place your SAT or ACT score and GPA against a college's middle 50% and acceptance rate to see whether it is a…

• Color Converter

  Convert colours between HEX, RGB, HSL, HSV and CMYK, with the colour's luminance and whether white or black text reads best on…

• Combination Calculator

  Count combinations — the ways to choose r items from n when order does not matter — with or without repetition, as…

• Commercial Cleaning Cost Calculator

  Price an office or commercial cleaning contract from the area, visits per month, production rate, labour cost and markup, per visit and…

• Commute Cost Calculator

  What driving to work costs a day, week, month and year in fuel, parking and tolls, and how many hours a year…

• Compound Interest Calculator

  Compound a balance and regular contributions, and see the year growth finally overtakes what you have put in — which is later…

• Conception Date Calculator

  Work back to the likely conception date from a due date, last period or birth date — with an honest range, since…

• Concrete Block Wall Calculator

  Work out the grout and rebar for a reinforced 8 in concrete block wall: grouted cells or solid grouting, bond beam and…

• Concrete Calculator

  Concrete for slabs, columns and steps in cubic yards or cubic metres, with the ready-mix order to place and the number of…

• Concrete Footing Calculator

  Concrete for strip footings under walls or pad footings under posts, with the order, bags, and proportions checked against common rules of…

• Concrete Slab Calculator

  Concrete for a slab from its size and thickness, with waste, the ready-mix order, bags, optional cost, and what an extra inch…

• Cone Calculator

  Find a cone's volume, slant height, curved surface and total surface area from its radius and height, or from its slant height.

• Confidence Interval Calculator

  Find a confidence interval for a mean, from data or summary figures with the t or z value, or for a proportion…

• Contrast Ratio Calculator

  Check the contrast ratio between text and background colours and whether it passes WCAG AA and AAA for normal text, large text…

• Conversion Rate Calculator

  Conversion rate from visitors and conversions, revenue per visitor, and the extra conversions and revenue a higher target rate would bring.

• Cooking Measurement Converter

  Convert between teaspoons, tablespoons, cups, fluid ounces, pints, millilitres and litres, or between grams, ounces, pounds and kilograms.

• Correlation Calculator

  Find the Pearson correlation coefficient r between two sets of paired data, with r², a significance test and Spearman's rank correlation.

• Cost Per Use Calculator

  The real cost of something each time you use it, from price, how often you use it, how long it lasts, upkeep…

• Countdown Calculator

  Count down to any date and time in days, hours and minutes, with totals in hours, minutes and seconds — for events,…

• Countertop Square Footage Calculator

  Add up countertop square footage for up to three sections, including an island and backsplash, with the cost and number of stone…

• Coupon Stacking Calculator

  Stack a sale, a percentage coupon and a fixed-amount coupon to find the final price, the true combined discount, and which order…

• Covariance Calculator

  Find the sample or population covariance between two sets of paired data, with the direction of the relationship and the correlation.

• Covered Call Calculator

  Calculate the premium income, returns if called or not, breakeven and maximum profit when you sell a covered call on shares you…

• Credit Card Payoff Calculator

  What paying the minimum actually costs — modelled as a percentage of the balance, which is what makes a card debt last…

• Credit Hours Calculator

  Find how many terms and years are left to graduate from your credits, or convert between semester, quarter and ECTS credits.

• Cribbage Hand Calculator

  Score a cribbage hand or crib from four cards and the starter: fifteens, pairs, runs, flushes and his nobs, with a full…

• Cricket Run Rate Calculator

  Cricket current run rate from runs and overs, the projected score, and the required run rate to chase a target in a…

• Crushed Concrete Calculator

  Work out the tons of recycled crushed concrete for a base or driveway and compare its cost with virgin crushed stone for…

• Crusher Run Calculator

  Work out the tons of crusher run for a compacted base, allowing for compaction, with the loose depth to spread and the…

• Cube Root Calculator

  Find the cube root of any number, including negatives, in exact simplified form where possible, or cube a number.

• Cumulative GPA Calculator

  Combine your current GPA with a new term's grades, or find the term GPA you need to reach a target cumulative GPA.

• Cups to Grams Calculator

  Convert cups to grams for flour, sugar, butter, honey, milk, oats and more, using typical weights per US or metric cup.

• Curve Grade Calculator

  See what a curved test score would be with a flat curve, proportional scaling, the square-root curve or a target class average.

• Customer Acquisition Cost Calculator

  Customer acquisition cost from marketing, sales and other spending and new customers won, with LTV:CAC and the payback period.

• Customer Lifetime Value Calculator

  Customer lifetime value from order value, purchase frequency, gross margin and customer lifespan, with the LTV:CAC ratio and CAC payback period.

• Cycling Power Calculator

  Estimate the watts needed to ride at a speed from your weight, bike, gradient, position and road surface, with W/kg and where…

• Cycling Speed Calculator

  Work out cycling speed from your gear and cadence, with gear inches and distance per pedal turn, or the speed a power…

• Cylinder Calculator

  Find a cylinder's volume, surface area and capacity in litres from its radius and height — or work backwards from a required…

• Dart Checkout Calculator

  A three-dart checkout route for any score from 2 to 170 finishing on a double, with the bogey numbers and what to…

• Data Storage Converter

  Convert data sizes between bits, bytes, KB, MB, GB, TB and PB, and binary KiB, MiB, GiB and TiB.

• Data Transfer Rate Converter

  Convert data rates between bps, kbps, Mbps and Gbps and bytes per second (kB/s, MB/s, GB/s, MiB/s), with transfer times.

• Date Calculator

  Add or subtract years, months, weeks and days from any date to find the resulting date and weekday, with month-end dates handled.

• Date Difference Calculator

  Find the difference between two dates in years, months and days, plus totals in weeks, days, hours, minutes and weekdays.

• Day of the Week Calculator

  Find the day of the week for any date in history or the future, with the day of the year and the…

• Days Between Dates Calculator

  Count the days between two dates, with or without the end date, split into weekdays and weekend days and into weeks and…

• Days Until Calculator

  Count the days until any date — a holiday, birthday or event — with weeks, weekdays, weekends and sleeps, or the days…

• Deadline Calculator

  Find a deadline a number of calendar or business days after a start date, skipping weekends and holidays, with weekend roll-over.

• Debt Consolidation Calculator

  Compares consolidation on total cost rather than the monthly payment, and separates a better rate from a longer term.

• Debt Snowball Calculator

  Snowball against avalanche, with both computed — so you can see exactly what choosing the motivating order costs in money.

• Debt to Income Calculator

  The ratio lenders use, and the one your bank account experiences — which is always larger, because DTI is calculated on gross…

• Decimal Time Converter

  Convert decimal hours to hours, minutes and seconds — or hours and minutes to decimal hours — for timesheets, payroll and invoicing.

• Decimal to Fraction Calculator

  Turn any decimal into an exact fraction in lowest terms, including repeating decimals such as 0.1666 recurring.

• Deck Board Calculator

  How many deck boards to buy, rows across the deck, and screws or hidden clips, from the deck size, board width, gap…

• Deck Calculator

  Framing take-off for a deck: joists, hangers, ledger, rim, beam, posts and footing concrete, from the deck size and spacings.

• Deck Footing Calculator

  Size deck footings from the load each post carries and the soil bearing capacity, with the concrete volume and bags for every…

• Deck Joist Calculator

  Count the deck joists you need for a given deck length and spacing, and check the joist span against IRC limits for…

• Deck Post Spacing Calculator

  Work out how many deck posts each beam needs and how far apart to set them, with cantilever checks and the total…

• Density Calculator

  Calculate density from mass and volume, or mass or volume from density, in any units, with the closest common material and whether…

• Dice Roller

  Roll virtual dice — any number of d4, d6, d8, d10, d12, d20 or d100 with a modifier — and see the…

• Dilution Calculator

  Mix a dilution ratio such as 1:200 or 1:400 to any volume, or solve C1V1 = C2V2 for the stock volume, final…

• Dirt Calculator

  Find how many cubic yards of dirt you need for an area and depth, with the weight, dump-truck loads and the delivered…

• Dirt Volume Calculator

  Find the volume of dirt in a pit, round hole, trench, cone-shaped pile or berm, in bank yards and loose yards after…

• Discount Calculator

  Price after a percentage or amount off, with stacked discounts combined correctly, or the original price behind a sale price.

• Discriminant Calculator

  Find the discriminant of a quadratic or cubic and what it says about the roots: how many are real, whether they repeat…

• Distance Formula Calculator

  Find the straight-line distance between two points in 2D or 3D, with the exact simplified surd as well as the decimal.

• Dividend Calculator

  Project dividend income with yield on cost, reinvestment, and the total return — because a yield on its own tells you almost…

• Dog Age Calculator

  Your dog's age in human years by size, from the veterinary chart and the DNA-based formula, with its life stage — and…

• Dollar Cost Averaging Calculator

  Averaging in against a lump sum, with both computed — including the finding most calculators leave out, which is that the lump…

• Doubling Time Calculator

  How long a quantity takes to double at a steady growth rate, exactly and by the rule of 72, or the halving…

• Down Payment Calculator

  How much deposit you need and how long it takes to save — counting the fact that house prices move while you…

• Download Time Calculator

  How long a download or upload takes from the file size and your connection speed, with overhead, the real transfer rate and…

• DPI Calculator

  The DPI (dots per inch) of a print from the image's pixels and the printed size, with print quality and the largest…

• Drywall Calculator

  Sheets of drywall or plasterboard for a room's walls and ceiling, less openings, with waste, screws and how many sheets other sizes…

• Dynasty Baseball Trade Calculator

  Compare both sides of a dynasty fantasy baseball trade by projected WAR over several seasons, adjusted for age and discounted for the…

• eGFR Calculator

  Estimate kidney function from creatinine, age and sex with the 2021 CKD-EPI equation — the version without a race coefficient — and…

• Electrical Load Calculator

  Estimate a home's electrical load and service size with the NEC 220.82 optional method: floor area, appliances and heating or cooling.

• Electricity Cost Calculator

  What any electrical device costs to run per hour, day, month and year from its wattage, hours of use and your price…

• Elo Rating Calculator

  New Elo ratings after a game from both players' ratings and the result, with the expected score and the K-factor used in…

• Emergency Fund Calculator

  Size an emergency fund from your essential costs and your actual circumstances, rather than the one-size-fits-all three to six months.

• Employee Cost Calculator

  The true annual cost of an employee: salary plus employer taxes, retirement, benefits and other costs, as a multiple of salary and…

• Energy Converter

  Convert energy between joules, kilojoules, calories, kilocalories, kWh, BTU, therms, foot-pounds and electronvolts.

• ERA Calculator

  Earned run average for a baseball or softball pitcher from earned runs and innings pitched, with WHIP and support for partial innings.

• Essay Word Count Planner

  Split an essay's word limit into an introduction, body paragraphs and a conclusion, with paragraph-length advice and drafting time.

• EV Charging Cost Calculator

  Cost and time to charge an electric car from any charge level, with range added, cost per mile or km, and a…

• Exam Countdown Calculator

  Count the days to your exam, the study days left after rest days, the total study hours and the hours available for…

• Excavation Calculator

  Soil to dig out for a foundation, pond or trench: in-ground volume, loose volume after swell, truckloads or skips, weight and removal…

• Exercise Hydration Calculator

  Plan how much to drink before, during and after exercise from your weight, the session length and your sweat rate, with sodium…

• Exponent Calculator

  Raise any number to any power, including negative and fractional exponents, or solve for the base or the exponent itself.

• Exponential Increase Calculator

  Calculate exponential increase by a fixed percentage per period: the final value, the growth rate needed or the periods to reach a…

• Factorial Calculator

  Work out the factorial of any whole number, exactly for large values, with the trailing-zero count and digit length.

• Fahrenheit to Celsius Calculator

  Convert degrees Fahrenheit to Celsius with the formula shown step by step, plus kelvin and a quick mental estimate.

• Fantasy Basketball Trade Calculator

  Compare a fantasy basketball trade by rest-of-season fantasy points, counting the roster spot a 2-for-1 deal frees or costs at waiver level.

• Fantasy Football Points Calculator

  Calculate a player's fantasy football points from passing, rushing and receiving stats in standard, half-PPR or full-PPR scoring.

• Fat Intake Calculator

  Daily fat in grams, with the part that is genuinely essential separated out — it is about a quarter of the usual…

• Fault Current Calculator

  Estimate available short-circuit current at a transformer and at the end of a conductor run using the point-to-point method.

• Feet to Meters Calculator

  Convert feet, or feet and inches such as a height, to metres, with centimetres, millimetres and yards.

• Fence Calculator

  Posts, rails, boards and post-hole concrete for a wooden fence, from its length, height, post spacing, gates and board size.

• Fence Post Depth Calculator

  Find how deep to set fence posts from the fence height, frost depth, post type and soil, with the hole size and…

• Fiber Intake Calculator

  Fibre from the figure the flat targets are actually derived from — 14 g per 1,000 calories — so the target scales…

• Fibonacci Calculator

  Find any Fibonacci number exactly, list the sequence, check whether a number belongs to it, and see how it approaches the golden…

• File Size Calculator

  Convert file and storage sizes between bytes, KB, MB, GB and TB, their binary KiB, MiB, GiB and TiB equivalents, and bits.

• Fill Dirt Calculator

  Work out how much loose fill dirt to order to raise the ground by a compacted height, allowing for shrinkage, with truckloads…

• Final Grade Calculator

  Find the score you need on your final exam to reach a target course grade, or the course grade a given final…

• Fish Tank Stocking Calculator

  Find how many fish of one adult size your tank can hold by the inch-per-gallon and surface-area rules, using whichever limit is…

• Five Number Summary Calculator

  Find the five-number summary of a data set — minimum, Q1, median, Q3 and maximum — with the box plot, IQR and…

• Flooring Calculator

  Boxes of wood, vinyl or laminate flooring for a room — including L-shaped rooms — with waste set by the laying pattern…

• Flour Conversion Calculator

  Convert flour between cups, tablespoons, grams and ounces for plain, bread, whole wheat, cake, self-raising and almond flour, spooned or scooped.

• Force Calculator

  Calculate force from mass and acceleration with Newton's second law, or mass or acceleration from force, in newtons, pounds-force and kgf.

• Fourier Series Calculator

  Find the Fourier series coefficients a0, an and bn of a function on [−L, L], the first N terms of the series…

• Fraction Calculator

  Add, subtract, multiply or divide two fractions, with the result reduced to lowest terms and shown as a decimal.

• Fraction to Decimal Calculator

  Convert any fraction to a decimal, with repeating digits identified and the length of the repeating block shown.

• Fraction to Percent Calculator

  Convert a fraction to a percentage, or turn a percentage back into a fraction in lowest terms.

• Free Fall Calculator

  Work out how long an object takes to fall from a height and how fast it lands, or how far it falls…

• Freelance Rate Calculator

  Day, week and month rates from an hourly rate, and a fixed project price from estimated hours with a contingency built in.

• Frequency Calculator

  Calculate frequency from a period, from wave speed and wavelength, from angular frequency or from rpm, with the period and angular frequency.

• Friction Calculator

  Calculate friction force from the coefficient of friction and normal force or mass, on the flat or a slope, and whether an…

• Friction Loss Calculator

  Calculate water friction loss in a pipe with the Hazen–Williams formula from flow, inside diameter, length and pipe material, with head and…

• Fuel Consumption Calculator

  Fuel consumption from a trip's distance and fuel used, or convert between L/100 km, km per litre, US mpg and UK mpg.

• Fuel Cost Calculator

  What a journey costs in fuel from the distance, your car's fuel economy and the fuel price, in US, UK or metric…

• Fuel Economy Converter

  Convert fuel economy between US mpg, UK mpg, litres per 100 km and km per litre, with fuel for 100 km and…

• Future Value Calculator

  What an amount today and a stream of payments become — and what delaying the start by a few years actually costs,…

• Gallons to Liters Calculator

  Convert US or UK gallons to litres exactly, with millilitres, the other gallon, and a price per litre from a price per…

• Gas Bill Calculator

  Turn gas meter readings into kWh or therms and a bill, with the unit rate, standing charge and tax, for metric or…

• GCF Calculator

  Find the greatest common factor of two or more numbers, by prime factorisation and by the Euclidean algorithm, with both methods shown.

• Gear Ratio Speed Calculator

  Calculate output rpm, gear ratio and torque multiplication through one or two gear stages, and the wheel speed in mph or km/h.

• Geometric Mean Calculator

  Find the geometric mean of positive numbers, or the true average growth rate of percentage returns, with the working shown.

• Geometric Sequence Calculator

  Find any term of a geometric sequence, the sum of its first n terms, or the infinite sum when the ratio is…

• Gift Budget Calculator

  Plan a holiday or birthday gift budget: people in each group and what to spend on each, plus wrapping, cards and shipping,…

• Golf Handicap Calculator

  Your World Handicap System handicap index from your recent scores, course ratings and slopes, with each score differential and your course handicap.

• Golf Score Calculator

  Add up a golf scorecard hole by hole: total, score to par, front and back nine, birdies and bogeys, Stableford points and…

• Golf Swing Weight Calculator

  Work out a golf club's swing weight on the Lorythmic scale from its total weight and balance point, and the head weight…

• GPA Calculator

  Calculate your grade point average from your courses, credits and letter grades or grade points, on the 4.0 or 4.3 scale.

• Grade Calculator

  Work out your weighted course grade from assignments, quizzes and exams, entered as percentages or points, with the letter grade.

• Grams to Cups Calculator

  Convert grams to cups for flour, sugar, butter, liquids and more, as decimal cups and as a measurable mix of cups, tablespoons…

• Grams to Ounces Calculator

  Convert grams to ounces exactly, with pounds, troy ounces for gold and silver, and the nearest quarter ounce for cooking.

• Gravel Calculator

  Gravel for a path, driveway or border from its size and depth: tons or tonnes, cubic yards or m³, bags, bulk bags…

• Grocery Budget Calculator

  A weekly, monthly and yearly grocery budget for your household from adults, children and your food cost per adult, with the cost…

• Gross Profit Calculator

  Gross profit and gross margin from sales, returns and the cost of goods sold, with the COGS ratio and the equivalent markup.

• Grout Calculator

  Grout for a tiled area from the tile size, thickness and joint width, using the manufacturers' formula — and why small tiles…

• Gutter Fall Calculator

  Check an existing gutter from its measured fall: slope per 10 ft, percent and degrees, whether it drains properly and the drop…

• Gutter Installation Cost Calculator

  Estimate the cost of installing gutters by material and length, with downspouts, gutter guards and removal of old gutters.

• Gutter Slope Calculator

  Set out the drop for a new gutter run: total fall at your chosen slope, chalk-line layout, split runs over 40 ft…

• Half Birthday Calculator

  Find your half birthday — six months after your birthday — with a countdown, the age you turn and the exact midpoint…

• Half-Life Calculator

  Work out how much of a substance remains after a time, its half-life, or the time to decay to an amount, with…

• Hardwood Floor Calculator

  Cartons of solid hardwood flooring with waste set by grade and pattern, plus a moisture check between the boards and the subfloor.

• Harmonic Mean Calculator

  Find the harmonic mean of positive numbers — the right average for speeds and rates over equal amounts — compared with the…

• Heart Rate Zone Calculator

  Work out your five heart rate training zones from your age or measured maximum, using percent of max or the Karvonen reserve…

• Heat Pump Cost Calculator

  Estimate the size and installed cost of a heat pump from your home's area and system type, with rebates and payback against…

• Hectares to Acres Calculator

  Convert hectares to acres exactly, with square metres, square kilometres, square feet and a price per hectare as a price per acre.

• Hex Calculator

  Add, subtract, multiply and divide hexadecimal numbers, convert to decimal and binary, and read hex colour codes and byte values.

• Home Addition Cost Calculator

  Estimate the cost of a home addition from its size and type, a room addition, second storey, sunroom or garage, with design,…

• Home Equity Calculator

  How much equity you have, how much of it you could actually borrow against, and how much of it you earned rather…

• Hourly Rate Calculator

  The hourly rate a freelancer or contractor needs to charge, worked back from target take-home pay, tax, expenses and billable hours.

• Hourly to Salary Calculator

  What hourly rate actually matches a salary, once unpaid leave, employer pension and the security you are not getting are priced in.

• Hours Calculator

  Find the hours and minutes between two times — including overnight and across dates — less any break, in hours, decimal and…

• House Cleaning Cost Calculator

  Estimate the price of a house clean from bedrooms, bathrooms, type of clean and hourly rate, with recurring-service discounts and monthly cost.

• House Flipping Calculator

  Work out the profit, ROI and annualised return on a house flip after buying costs, repairs, holding costs, loan interest and selling…

• Ideal Gas Law Calculator

  Solve PV = nRT for pressure, volume, moles or temperature, in atm, kPa, bar, psi, litres, cubic metres, kelvin, Celsius or Fahrenheit.

• Ideal Weight Calculator

  Four ideal weight formulas side by side, what each was actually built for, and the healthy BMI range — the only one…

• Image Resize Calculator

  New pixel dimensions for an image resized by a percentage, to a width or height, or to fit inside a box, keeping…

• Inches to cm Calculator

  Convert inches, or feet and inches such as a height, to centimetres, metres and millimetres exactly.

• Inflation Calculator

  What money is worth at another point in time — and whether a pay rise actually was one, which is the question…

• Insulation Calculator

  How thick insulation must be to reach a target R-value, in US or SI units, for common materials, with the amount to…

• Interest Rate Calculator

  Work backwards to the rate: from a loan quoted only as a monthly payment, from something that grew, or from a savings…

• Interquartile Range Calculator

  Find the interquartile range (IQR) of a data set with Q1, the median and Q3, the 1.5 × IQR outlier fences and…

• Inventory Turnover Calculator

  Inventory turnover and days of stock on hand from cost of goods sold and beginning and ending inventory, for any period.

• Investment Calculator

  Project an investment with the two things a compound interest calculator leaves out: annual charges, and the gap between an average return…

• Invoice Calculator

  Invoice total from up to three line items, with a discount before tax, sales tax or VAT, shipping and the balance after…

• IRA Calculator

  Project an IRA, see exactly how much the income phase-out reduces your contribution, and where an IRA belongs in the order of…

• IRR Calculator

  The rate a project's cash flows imply — with the reinvestment assumption made explicit, and a warning when the flows have more…

• Joules to Calories Calculator

  Convert joules to calories and kilocalories exactly, with kilojoules, International Table calories and watt-hours.

• Junk Removal Cost Calculator

  Estimate junk removal costs from the volume of junk as a share of a truckload, with minimum charges and fees for heavy…

• kg to Pounds Calculator

  Convert kilograms to pounds exactly, with pounds and ounces, stone and pounds, and total ounces.

• Kinetic Energy Calculator

  Calculate kinetic energy from mass and speed, or the mass or speed for a given energy, in joules, kJ, kWh and kcal.

• km to Miles Calculator

  Convert kilometres to miles exactly, with yards or feet, nautical miles and walking and driving times.

• Knots to mph Calculator

  Convert knots to miles per hour and km/h exactly, with metres per second, distance per day and the Beaufort wind force.

• Laminate Flooring Calculator

  Planks and packs of laminate for a room, plus a row plan that shows how wide the last row will be and…

• Landscape Material Calculator

  Get quantities of mulch, topsoil, compost, decorative gravel and paver sand for one area at once, in cubic yards, tons and retail…

• Lap Average Calculator

  Average a set of lap times with the total, fastest and slowest laps, pacing consistency, each lap against the average, and speed.

• Late Payment Interest Calculator

  Interest on an overdue invoice from the amount, annual rate and days late, with the daily rate, total claim and cost of…

• Laundry Cost Calculator

  What each load of laundry costs at home in electricity, water, detergent and tumble drying, per week and year, against a laundromat.

• Law School Acceptance Calculator

  Estimate your chance of at least one law school acceptance from the number of reach, target and likely schools on your list…

• Law School Admissions Calculator

  See where your LSAT and GPA fall against a law school's 25th, median and 75th percentile figures, and whether it is a…

• Law School GPA Calculator

  Calculate your LSAC GPA for law school applications, with A+ counted as 4.33 and repeated courses included, beside your 4.0-capped college GPA.

• Lawn Mowing Time Calculator

  How long it takes to mow a lawn from its area, the mower's cutting width and your speed, allowing for overlap and…

• LCM Calculator

  Find the lowest common multiple of two or more numbers, by prime factorisation and via the greatest common factor, with both routes…

• Lead Time Calculator

  Add up supplier lead time from processing, production and transit days, then work out safety stock and the reorder point for your…

• League Points Calculator

  League table points from wins, draws and losses, with points per game, goal difference, the season pace and the maximum points still…

• Lean Body Mass Calculator

  Lean mass from body fat or from height and weight — with the James formula refused past the point where it reports…

• Lean Gain Calculator

  Plan a lean bulk: a target rate of weight gain for your training level, the daily calorie surplus, protein and how long…

• Leap Year Calculator

  Check whether any year is a leap year with the rule explained, find the previous and next leap years, or count leap…

• Length Converter

  Convert lengths and distances between millimetres, centimetres, metres, kilometres, inches, feet, yards and miles.

• Lens Calculator

  Use the thin lens equation to find the image distance, object distance or focal length, with the magnification and image type.

• Letter Grade Converter

  Convert a percentage to a letter grade and GPA points, or a letter grade to its percentage range, on plus/minus or plain…

• Limestone Calculator

  Work out how many tons of crushed limestone you need by grade, #57, #411, #3 or screenings, with truckloads and cost for…

• Linear Equation Calculator

  Solve a linear equation for x, with variables on one side or both, and see the degenerate cases explained rather than hidden.

• Linear Regression Calculator

  Fit a least-squares regression line ŷ = a + bx to paired data, with the slope, intercept, R², slope test and predictions.

• Liters to Gallons Calculator

  Convert litres to US and UK gallons exactly, with quarts, pints and fluid ounces, and a price per gallon from a price…

• Loan Calculator

  Work out the monthly payment on a loan, the total interest it will cost, and how long it takes to clear —…

• Loan Payoff Calculator

  Start from the balance you owe today and see how fast you can clear it — and whether a lump sum or…

• Logarithm Calculator

  Find a logarithm in any base, including natural and base 10, or solve for the base or the value the logarithm is…

• Long Division Calculator

  Divide one number by another and see every step of the long division, with a remainder or carried out to decimal places.

• Lottery Odds Calculator

  Odds of winning any lottery from the numbers picked and the pool size, with bonus balls, odds of matching fewer numbers and…

• LVL Span Calculator

  Estimate how far a 1¾ in LVL beam can span for its depth, number of plies and the floor load it carries,…

• Macro Calculator

  Protein, carbs and fat in grams — with protein checked per kilogram of bodyweight, because a percentage is the wrong unit for…

• Map Scale Calculator

  Convert map distances to real distances and back at any scale such as 1:25,000, or find a map's scale from a known…

• Marathon Time Calculator

  Find the pace and split times for a marathon goal, or the finish time for a pace, with 5K splits and an…

• Margin of Error Calculator

  Find the margin of error for a survey percentage or a sample mean at any confidence level, with an optional finite population…

• Markup Calculator

  Selling price from cost and markup, the markup between a cost and a price, or the cost that fits a price —…

• Material Calculator

  Work out the volume and weight of any bulk material, from gravel and sand to mulch and concrete, for an area and…

• Matrix Calculator

  Add, subtract and multiply matrices, or find the determinant, inverse and transpose of a 2×2 or 3×3, with the working shown.

• Max Heart Rate Calculator

  Your maximum heart rate from every well-founded formula side by side, with the individual scatter shown — it is bigger than the…

• Mean Median Mode Calculator

  Find the mean, median and mode of a list of numbers with each step shown, a frequency count and what the gap…

• Meat Portion Calculator

  How much raw meat or fish to buy per person and for a group — boneless, bone-in, whole birds, ribs, mince or…

• Meters to Feet Calculator

  Convert metres to feet, and to feet and inches, inches and yards, using the exact factor of 0.3048 metres per foot.

• Midpoint Calculator

  Find the midpoint between two points, or work backwards from a midpoint and one endpoint to find the missing endpoint.

• Miles to km Calculator

  Convert miles to kilometres exactly, with metres, nautical miles and walking and driving times.

• Military PT Test Calculator

  Check push-up, core and run results against your branch's minimums, see where you pass or fall short, and the run pace per…

• Military Time Converter

  Convert standard 12-hour am/pm time to 24-hour military time and back, with how it is said aloud, like fourteen thirty hours.

• Minutes to Hours Calculator

  Convert minutes to hours and minutes and to decimal hours — or hours to minutes — with seconds and days, and the…

• Mixed Number Calculator

  Convert between mixed numbers and improper fractions, or add, subtract, multiply and divide two mixed numbers.

• ml to oz Calculator

  Convert millilitres to US or UK fluid ounces exactly, with cups, tablespoons and teaspoons and the weight of the same volume of…

• Molar Mass Calculator

  Find the molar mass of any chemical formula, with brackets and hydrates, the percentage of each element and moles from a sample…

• Molarity Calculator

  Work out the molarity of a solution, the mass of solute to weigh out, or the volume to make up, from a…

• Momentum Calculator

  Calculate momentum from mass and velocity, or mass or velocity from momentum, with kinetic energy and the force needed to stop it.

• Months Between Dates Calculator

  Find the number of months between two dates — whole months and days, as a decimal, and by average month length —…

• Moon Phase Calculator

  Find the Moon's phase, age and illumination for any date, with the exact times of the next new, first quarter, full and…

• Mortar Calculator

  Mortar for brick or block walls from the wall area, with the cement bags and sand to buy at your mix ratio…

• Mortgage Affordability Calculator

  Work backwards from your income to the price a lender would approve, through both debt-to-income limits — and see which one is…

• Mortgage Calculator

  The full monthly cost of a mortgage — principal, interest, property tax, insurance and PMI — with the date the mortgage insurance…

• Moving Cost Calculator

  Estimate the cost of moving house yourself with a rental truck or with professional movers, from home size and distance, including packing.

• MPG Calculator

  Your car's real miles per gallon from a fill-up: miles from the odometer or trip meter and fuel added, with L/100 km…

• mph to km/h Calculator

  Convert miles per hour to kilometres per hour exactly, with metres and feet per second and the distance covered each second.

• Mulch Calculator

  Mulch for beds and borders from the area and depth: cubic yards or m³ with settling, bags, bulk bags, coverage and optional…

• Multiplication Table Generator

  Generate the times table for any number, or a full grid up to any size, with the patterns that make each table…

• Net Present Value Calculator

  Discount a project's cash flows back to today, and see the discount rate at which the decision flips — because that rate…

• Net Profit Calculator

  Net profit and net margin from revenue, cost of goods, operating expenses, interest and tax, with gross and operating profit along the…

• Net Worth Calculator

  Assets minus liabilities, and then the figure that actually governs decisions — how much of it you could reach this month.

• Normal Distribution Calculator

  Find probabilities under a normal curve — below, above or between values — or the value at any percentile, for any mean…

• Number Base Converter

  Convert a number between any two bases from 2 to 36, with every common base shown alongside and exact arithmetic at any…

• Number to Words Converter

  Write any number out in English words — whole numbers, decimals and negatives, ordinals like twenty-first, and cheque style — in US…

• Odds Calculator

  Convert odds to probability and back, and between fractional, decimal and American odds, with the fair payout on a stake.

• Odds Ratio Calculator

  Find the odds ratio from a 2 × 2 table of exposure and outcome, with its confidence interval, z test and p-value.

• Ohm’s Law Calculator

  Enter any two of voltage, current, resistance and power to find the other two with Ohm's law and the power formulas.

• On-Base Percentage Calculator

  On-base percentage from hits, walks, hit-by-pitches, at-bats and sacrifice flies, with OPS when you add slugging percentage.

• One Rep Max Calculator

  Estimate your one rep max from a set of several reps with seven published formulas, plus the training loads from 60 to…

• Ounces to Grams Calculator

  Convert ounces to grams exactly, for everyday (avoirdupois) ounces or troy ounces used for gold and silver.

• Outlier Calculator

  Find outliers in a data set with the 1.5 × IQR rule or a z-score threshold, and see how the mean and…

• Oven Temperature Converter

  Convert oven temperatures between Fahrenheit, Celsius, fan (convection) Celsius and gas marks, with the figures recipes actually use.

• Overtime Calculator

  What overtime actually pays after tax — and the point at which extra hours start being worth materially less than the earlier…

• Ovulation Calculator

  Estimate ovulation and your six-day fertile window by counting back from your next period, for this cycle and the next two.

• P-Value Calculator

  Find the p-value from a z score, a t statistic with degrees of freedom, or a chi-square statistic, one- or two-tailed, with…

• Pace Calculator

  Work out running or walking pace from distance and time, or the finish time or distance from a pace, in minutes per…

• Paint Calculator

  Paint for a room's walls and ceiling from its size, coats and the paint's coverage, rounded to the cans you can actually…

• Pakistan Income Tax Calculator

  Salaried income tax under the slab system, with every slab editable — because they are set by the annual Finance Act and…

• Party Drinks Calculator

  How much beer, wine, spirits, soft drinks and ice to buy for a party, from the number of guests and how long…

• Pass Fail Calculator

  Check whether a score passes against a pass mark, see your percentage and find how many marks you are above or below…

• Passer Rating Calculator

  NFL passer rating or NCAA passing efficiency for a quarterback from attempts, completions, yards, touchdowns and interceptions.

• Password Generator

  Generate strong random passwords of any length with letters, digits and symbols, optionally without look-alike characters, with their strength in bits.

• Password Strength Calculator

  Check how strong a password is: its entropy in bits, how long a brute-force attack would take, and whether it uses common…

• Pasta Portion Calculator

  How much dry or fresh pasta to cook per person and for a group, with the cooked weight, water and salt for…

• Pavement Calculator

  Find how far a load of asphalt will pave at your width and thickness, using the spread rate in pounds per square…

• Paycheck Calculator

  Gross to net at your own rates — with the thing payslips hide, which is that a pension contribution costs far less…

• Payroll Calculator

  Gross pay, deductions, net pay and total employer cost for one pay period, hourly with overtime or salaried, weekly to monthly.

• Pea Gravel Calculator

  Work out how much pea gravel you need and whether buying 0.5 cubic foot bags or a bulk delivery by the ton…

• Pension Calculator

  What a defined benefit pension pays, and the capital sum it is actually worth — which is usually far more than people…

• Percent Error Calculator

  Compare a measured or estimated value against the accepted true value, and express how far off it was as a percentage.

• Percentage Calculator

  Work out a percentage of a number, what percentage one number is of another, or the percentage change between two values.

• Percentage Decrease Calculator

  Find the percentage drop between two values, take a percentage off a number, or work backwards to the price before a discount.

• Percentage Difference Calculator

  Compare two values where neither is a baseline. Divides by their average, so the answer is the same whichever order you enter…

• Percentage Increase Calculator

  Find the percentage increase between two values, or apply an increase to a number to see what it becomes.

• Percentage to GPA Calculator

  Convert a percentage grade to a GPA and letter grade on the 4.0 scale, with proportional and ten-point conversions for comparison.

• Percentile Calculator

  Find the value at any percentile of a data set, or the percentile rank of a value, with the position and interpolation…

• Perimeter Calculator

  Find the perimeter of a rectangle, triangle, circle, parallelogram, trapezoid, regular polygon or ellipse — the distance all the way round.

• Period Calculator

  Predict your next six periods from your last one and your cycle length, with ovulation, fertile days and whether your cycle is…

• Permutation Calculator

  Count permutations — the ways to arrange r items from n when order matters — with or without repetition, as exact numbers.

• Personal Loan Calculator

  Work out a personal loan payment and the true APR once the origination fee is deducted — because the money that reaches…

• Pet Food Calculator

  How many calories your dog or cat needs a day from weight and life stage, and how many cups or grams of…

• pH Calculator

  Calculate pH from hydrogen or hydroxide ion concentration, convert pH to concentrations and pOH, or find the pH of a weak acid…

• Phone Plan Comparison Calculator

  Compare two mobile phone plans — a contract with the phone included against buying the phone and a SIM-only plan — over…

• Pizza Size Calculator

  Compare two pizza sizes or deals by area and price per square inch to see which is really the better value.

• Plaster Calculator

  Bags of plaster for a wall or ceiling from the area, coat thickness and product coverage, for finish skims and undercoats alike.

• Points Per Game Calculator

  Points per game from total points and games played, the season pace, and the scoring needed to reach a target average.

• Poisson Distribution Calculator

  Find Poisson probabilities — exactly k events, at most, at least, fewer or more — from an average rate per interval.

• Polygon Calculator

  Find the area, perimeter, angles, apothem and radius of a regular polygon from its side length, apothem or circumradius.

• Polynomial Multiplication Calculator

  Multiply two or three polynomials and expand the product, with every term-by-term product, FOIL for binomials and the degree of the result.

• Pond Calculator

  Work out a garden pond's water volume in gallons, the pump size for your turnover time and the liner size from its…

• Pond Size Calculator

  Work out how big a pond your koi or goldfish need: minimum gallons, surface area at your depth and pond dimensions to…

• Post Hole Concrete Calculator

  Concrete for fence and deck post holes, less the volume the post itself fills, in bags per hole and in total, with…

• Potential Energy Calculator

  Calculate gravitational potential energy from mass and height, or the mass or height for an energy, on Earth, the Moon or other…

• Pounds to kg Calculator

  Convert pounds, or pounds and ounces, to kilograms and grams exactly, with total ounces and stone.

• Power Converter

  Convert power between watts, kilowatts, megawatts, horsepower, metric horsepower, BTU per hour and foot-pounds per second.

• Power Physics Calculator

  Calculate power from work and time or from force and speed, or the energy or time for a given power, in watts,…

• Pregnancy Due Date Calculator

  Your due date from your last period, conception date or IVF transfer, with the term window around it and the key dates…

• Pregnancy Week Calculator

  How many weeks and days pregnant you are on any date, from your last period or due date — with the age…

• Present Value Calculator

  What money arriving later is worth today — and, for a lump sum against a stream of payments, the exact rate at…

• Pressure Converter

  Convert pressure between psi, bar, kPa, pascals, atmospheres, millibars, mmHg and inches of mercury.

• Pressure Washing Estimate Calculator

  Estimate a pressure washing job by surface and area: siding, driveway, deck or roof, with sealing, minimum charge, travel and time on…

• Price Per Unit Calculator

  Compare up to three pack sizes by price per kg, 100 g, lb, litre, fl oz or item, with metric and US…

• Prime Factorization Calculator

  Break any whole number into its prime factors, with the factor tree, the exponent form, and every divisor it produces.

• Prime Number Checker

  Check whether a number is prime, see the divisor that rules it out, and find the nearest primes on either side.

• Primer Calculator

  Primer or a mist coat for a room from its size and the surface, which sets how far a litre goes —…

• Print Size Calculator

  How large an image can be printed at a chosen DPI, in inches and centimetres, and the DPI it reaches at common…

• Probability Calculator

  Find the probability of an event, of two independent events together or of either, and of something happening at least once in…

• Productivity Calculator

  Measure labour productivity as output per hour, per worker, and its change from an earlier period, with optional value per hour worked.

• Profit Margin Calculator

  Profit margin from cost and price, the price that hits a target margin, or the most you can pay — with markup…

• Projectile Motion Calculator

  Work out the range, flight time, maximum height and landing speed of a projectile from its launch speed, angle and height.

• Property Tax Calculator

  Property tax from market value through assessment ratio and exemptions, with the effective rate — the only figure comparable between places.

• Proportion Calculator

  Solve a proportion for its missing term by cross-multiplying, check whether two ratios match, or work with inverse proportion.

• Protein Intake Calculator

  Protein in grams a day, set against lean mass where bodyweight would overstate it — and measured against the RDA, which is…

• psi to bar Calculator

  Convert psi to bar exactly, with kPa, MPa and atmospheres, and the absolute pressure for a gauge reading such as a tyre.

• PTO Accrual Calculator

  Work out how much paid time off you earn each pay period or hour worked, and project your PTO balance after future…

• Pythagorean Theorem Calculator

  Find a missing side of a right triangle, or check whether three lengths form one, with the exact answer and both acute…

• Quadratic Equation Calculator

  Solve any quadratic equation, with the discriminant, the exact surd roots, the vertex and the factored form.

• Quartile Calculator

  Find the first, second and third quartiles of a data set by the textbook or spreadsheet method, with the halves, positions and…

• Quotient Rule Calculator

  Differentiate f(x) = u(x)/v(x) with the quotient rule, showing u′, v′, the substituted formula, the slope at a point and the tangent…

• R-Squared Calculator

  Find R², the coefficient of determination, from paired data, from a correlation, or from sums of squares, with adjusted R².

• Race Time Predictor

  Predict your times for 5K, 10K, half marathon and marathon from one recent race, using Riegel's formula, with the pace for each.

• Radians to Degrees Calculator

  Convert between radians, degrees, gradians and turns, with the exact multiple of pi shown wherever there is one.

• Raffle Odds Calculator

  Your chance of winning a raffle from your tickets, the total sold and the number of prizes, with expected prizes and the…

• Rafter Dimensions Calculator

  Work out rafter cut angles and birdsmouth dimensions from the pitch and rafter size: plumb and seat cuts, heel depth, height above…

• Rafter Length Calculator

  Common rafter length from the building span, roof pitch, overhang and ridge board, with the stock length to buy and the plumb…

• Random Number Generator

  Generate random whole numbers between any minimum and maximum — one or many, with or without repeats, sorted if you like —…

• Range Calculator

  Find the range of a list of numbers — the gap between the smallest and largest values — with the minimum, maximum…

• Ratio Calculator

  Simplify a ratio, scale it up or down, find a missing term, or split a total amount in a given ratio.

• Rational Algebraic Expressions Calculator

  Add, subtract, multiply or divide two rational expressions in x, reduce the result to lowest terms and list the excluded values of…

• Readability Score Calculator

  Score how easy any English text is to read with Flesch Reading Ease, Flesch–Kincaid grade, Gunning fog, Coleman–Liau and ARI.

• Reading Time Calculator

  Estimate how long it takes to read any text or book from its word count or pages and your reading speed, silently…

• Rebar Calculator

  Bars, total length, laps and weight for a reinforcing grid in a slab or footing, in US bar sizes or metric —…

• Recessed Lighting Calculator

  Work out how many recessed lights a room needs from its size, its use and the lumens of each fixture, with the…

• Recessed Lighting Layout Calculator

  Lay out recessed lights in an even grid from the room size and ceiling height: rows, columns, spacing and the distance from…

• Recipe Converter

  Convert a recipe to a different number of servings: every ingredient multiplied by the same factor, with spoon amounts made measurable.

• Recipe Scaling Calculator

  Scale one measured amount by a factor, by servings or by pan size, with the result in the same unit, other kitchen…

• Rectangle Calculator

  Find a rectangle's area, perimeter and diagonal from its sides — or work backwards from the area, perimeter or diagonal to a…

• Refinance Calculator

  Compare staying put against refinancing: the monthly saving, the break-even on fees, and whether restarting the clock costs more than the lower…

• Relative Risk Calculator

  Find the relative risk from a 2 × 2 table, with its confidence interval, the absolute risk difference and the number needed…

• Remainder Calculator

  Find the remainder when one number is divided by another, check divisibility, or work with modular arithmetic including large powers.

• Rent Split Calculator

  Split rent fairly between 2 to 4 housemates: equally, by bedroom size with shared space split evenly, or in proportion to income.

• Rent vs Buy Calculator

  Compares net wealth rather than monthly payments, counting what the deposit would earn invested and what it costs to both buy and…

• Rent vs Sell Calculator

  Compare selling your home now and investing the proceeds with renting it out for a few years and selling later, on wealth…

• Resistor Calculator

  Decode 4-band and 5-band resistor colour codes into ohms and tolerance, or find the colour bands for any resistor value.

• Resting Heart Rate Calculator

  Turn a pulse count into beats per minute, see how precise that count really is, and read the result against both the…

• Retirement Calculator

  Both halves of the problem: what the pot grows to, and whether it survives being drawn down once the income rises with…

• Revenue Calculator

  Revenue from price and units sold, net of returns, projected month by month with a growth rate, with the total, final month…

• Rice Water Ratio Calculator

  Water for cooking white, basmati, jasmine, sushi, brown or wild rice by the absorption method, with rice per person, cooked yield and…

• Right Triangle Calculator

  Solve a right triangle from any two of its measurements, including sides, angles, the altitude to the hypotenuse and both circle radii.

• Rip Rap Calculator

  Estimate the tons of rip rap stone to armour a bank or shoreline from its length, height and slope, with the layer…

• River Rock Calculator

  Find the tons of river rock for a landscape bed by stone size, with the right depth for each size, coverage per…

• RMS Calculator

  Calculate the root mean square of a list of numbers, or the RMS value of a sine, square, triangle or sawtooth wave…

• Road Trip Calculator

  Plan a road trip: driving time, days and nights on the road, fuel cost, lodging and food, with the total and the…

• Roast Cooking Time Calculator

  Roasting time for beef, lamb, pork or chicken by weight and doneness, with oven temperature, the internal temperature to aim for and…

• Rock Calculator

  Estimate the weight of a boulder or landscape rock from its size, shape and rock type, and see what equipment you need…

• ROI Calculator

  Work out return on investment including costs and income, annualise it so it can be compared, and separate the return on your…

• Roman Numeral Converter

  Convert numbers from 1 to 3,999 to Roman numerals, or Roman numerals back to numbers, with the breakdown of each symbol.

• Roof Pitch Calculator

  Convert a roof’s rise and run, or its angle, into pitch in 12, degrees, percent grade and pitch factor, with what the…

• Roofing Calculator

  The area of a roof in square feet, square metres and roofing squares, from the building footprint, overhang and pitch, with waste…

• Rounding Calculator

  Round a number to any number of decimal places or to the nearest ten, hundred or thousand, using the rounding rule you…

• RPE to Percentage Calculator

  Convert reps at an RPE into a percentage of your one rep max and a load, or estimate your one rep max…

• Rubric Score Calculator

  Add up rubric scores across criteria, with optional weights, and convert the total to a percentage and letter grade.

• Rucking Calorie Calculator

  Estimate calories burned rucking from your body weight, pack weight, speed, grade and terrain using the Pandolf load-carriage equation.

• Rule of 72 Calculator

  How long money takes to double, the exact answer beside the shortcut, and the rate where the rule of 72 is precisely…

• Running Record Calculator

  Score a reading running record: accuracy rate, reading level, error rate and self-correction rate, plus words correct per minute if timed.

• Salary Calculator

  Convert a salary between every period — and work out what you are really paid per hour once unpaid overtime and leave…

• Sales Commission Calculator

  Commission on sales at a flat rate or on a tiered accelerator plan, with base salary, total pay and the effective commission…

• Sales Tax Calculator

  Add tax to a price or take it back out — with the subtraction error shown beside the right answer, because it…

• Sample Mean Calculator

  Find the sample mean x̄ of your data with its standard deviation, standard error and a confidence interval for the population mean.

• Sample Size Calculator

  Find how many people to survey for a given margin of error and confidence level, for a percentage or a mean, with…

• Sand Calculator

  Sand for paver bedding, a pool base or a sandpit from the area and depth: tons or tonnes, cubic yards or m³,…

• Savings Calculator

  Project a savings plan in today's money, after tax — or find the monthly amount a goal needs once inflation has been…

• Savings Goal Calculator

  Put up to three goals against one monthly budget, and find out whether funding them one at a time reaches all of…

• Scale Model Calculator

  Convert real sizes to model sizes, or model sizes back to real ones, at any scale such as 1:24, 1:72 or HO…

• Scholarship Value Calculator

  Find a scholarship's total value, how much of your costs it covers, its value in work hours or per hour of applying,…

• Scientific Notation Calculator

  Convert between ordinary numbers and scientific notation, or multiply and divide two numbers written in it.

• Screen Size Calculator

  Width and height of a TV, monitor or phone screen from its diagonal and aspect ratio, in inches and centimetres, with pixel…

• Section 179 Calculator

  Estimate the Section 179 deduction for equipment or vehicles, applying business use, the annual limit, the phase-out and the business income limit.

• Seller Financing Calculator

  Work out the monthly payment on a seller-financed home sale, the balloon payment due and the interest the seller earns over the…

• Semester Grade Calculator

  Combine two term or quarter grades and a semester exam into your semester grade, or find the exam score you need for…

• Septic System Size Calculator

  Size a septic drain field from bedrooms and the perc test rate: absorption area in square feet, trench length and the number…

• Septic Tank Size Calculator

  Find the septic tank size you need in gallons from the number of bedrooms, with garbage disposal sizing and a pumping interval…

• Settlement Tax Calculator

  Estimate what you keep from a lawsuit settlement after attorney fees, costs and federal tax, for physical injury, employment or other claims.

• Severance Package Calculator

  Estimate a severance package from salary, years of service and weeks per year, with unused PTO, tax withholding and how many months…

• Shingle Calculator

  Bundles of asphalt shingles for a roof, plus hip and ridge cap, starter strip and roofing nails, from the roof area and…

• Shoe Size Converter

  Convert adult shoe sizes between UK, EU, US men's and US women's sizes, or from foot length, with the approximate foot length…

• Shopping Savings Calculator

  What a sale, cashback and loyalty rewards really save you on a purchase, the effective price you pay, and the saving over…

• Significant Figures Calculator

  Count the significant figures in a number, or round it to a chosen number of them, with the reason each digit counts…

• Sim Racing FOV Calculator

  Calculate the correct field of view for sim racing from your screen size, aspect ratio and eye distance, for single or triple…

• Simple Interest Calculator

  Solve I = P × r × t in any direction, with the gap against compound interest shown so you can see…

• Simplest Radical Form Calculator

  Write a square root, cube root or any nth root in simplest radical form, with prime factors shown and fractions under the…

• Simplify Fraction Calculator

  Reduce any fraction to its lowest terms, with the greatest common divisor and the full chain of equivalent fractions shown.

• Simplify Radical Expressions Calculator

  Add, subtract and multiply square roots: simplify each term, combine like radicals and get an exact answer such as 17√3 with a…