Statistics Calculators
Averages, spread, probability, sampling and distributions.
- 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 squared.
- Binomial Distribution Calculator Find binomial probabilities — exactly k successes, at most, at least, fewer or more — for n trials with a fixed chance of success.
- 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.
- Coefficient of Variation Calculator Find the coefficient of variation — the standard deviation as a percentage of the mean — from a data list or a known mean and SD.
- Combination Calculator Count combinations — the ways to choose r items from n when order does not matter — with or without repetition, as exact numbers.
- 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 with the Wilson interval.
- Correlation Calculator Find the Pearson correlation coefficient r between two sets of paired data, with r², a significance test and Spearman's rank correlation.
- Covariance Calculator Find the sample or population covariance between two sets of paired data, with the direction of the relationship and the correlation.
- 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 outlier fences.
- Geometric Mean Calculator Find the geometric mean of positive numbers, or the true average growth rate of percentage returns, with the working shown.
- Harmonic Mean Calculator Find the harmonic mean of positive numbers — the right average for speeds and rates over equal amounts — compared with the other means.
- 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 any outliers.
- Linear Regression Calculator Fit a least-squares regression line ŷ = a + bx to paired data, with the slope, intercept, R², slope test and predictions.
- 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 correction.
- 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 between mean and median shows.
- Normal Distribution Calculator Find probabilities under a normal curve — below, above or between values — or the value at any percentile, for any mean and SD.
- 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.
- 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 median change without them.
- 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 the decision.
- Percentile Calculator Find the value at any percentile of a data set, or the percentile rank of a value, with the position and interpolation shown.
- Permutation Calculator Count permutations — the ways to arrange r items from n when order matters — with or without repetition, as exact numbers.
- Poisson Distribution Calculator Find Poisson probabilities — exactly k events, at most, at least, fewer or more — from an average rate per interval.
- Probability Calculator Find the probability of an event, of two independent events together or of either, and of something happening at least once in repeated tries.
- Quartile Calculator Find the first, second and third quartiles of a data set by the textbook or spreadsheet method, with the halves, positions and IQR.
- R-Squared Calculator Find R², the coefficient of determination, from paired data, from a correlation, or from sums of squares, with adjusted R².
- Range Calculator Find the range of a list of numbers — the gap between the smallest and largest values — with the minimum, maximum and midrange.
- Relative Risk Calculator Find the relative risk from a 2 × 2 table, with its confidence interval, the absolute risk difference and the number needed to treat or harm.
- RMS Calculator Calculate the root mean square of a list of numbers, or the RMS value of a sine, square, triangle or sawtooth wave from its peak.
- 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 a finite population option.
- Standard Deviation Calculator Find the sample or population standard deviation of a list of numbers, with the mean, variance and every step of the working.
- Standard Error Calculator Find the standard error of a mean from data or from a standard deviation and sample size, or the standard error of a proportion.
- T-Test Calculator Run a one-sample, two-sample (Welch) or paired t-test, with the t statistic, degrees of freedom, p-value and a confidence interval.
- Variance Calculator Find the sample or population variance of a list of numbers, with a table of deviations and squared deviations and the standard deviation.
- Weighted Average Calculator Find the weighted average of a list of values from their weights, such as grades by credit or percentage, with the working shown.
- Z-Score Calculator Find the z-score of a value from the mean and standard deviation, or the value for a z-score, with the normal percentile and tail areas.