About the US Income Tax Calculator
Federal income tax and FICA on employment income.
The reason to build it is one belief that is both extremely common and exactly backwards:
"I don't want a raise — it'll push me into a higher bracket."
It cannot cost you money. Not at any income, not in any bracket, not ever. And rather than assert that, this US income tax calculator computes take-home either side of a crossing so you can watch it.
How to Use the US Income Tax Calculator
Enter your gross annual pay and filing status.
Pre-tax contributions — 401(k), HSA and similar — reduce taxable income dollar for dollar.
The standard deduction and Social Security wage base default to 2025 figures and are inputs, because both change every year.
Step-by-Step Example
$100,000, single, no pre-tax contributions.
Gross: 100,000
Less standard deduction: 15,000
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Taxable income: 85,000
11,925 at 10%: 1,192.50
36,550 at 12%: 4,386.00
36,525 at 22%: 8,035.50
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Federal income tax: 13,614.00
FICA: 7,650.00
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Take-home: 78,736.00Effective rate 21.26%. Tax bracket 22%. Marginal rate 29.65% once FICA is counted.
Why a Raise Cannot Cost You Money
Brackets are marginal. Only the dollars above a threshold are taxed at the higher rate; every dollar below it is taxed exactly as it was before.
Crossing into the 22% bracket does not tax your whole income at 22%. It taxes the portion above the threshold at 22%, and leaves everything beneath it untouched.
$63,000 gross → take-home rises
$64,000 gross → take-home rises againThe calculator checks this at every income from zero to $400,000 in its own test suite, and take-home never falls. Not once.
What is true is that the rate on the next dollar jumps. A raise past a threshold is worth less per dollar than the one before it. That is a real effect and a completely different claim from losing money — and conflating the two is precisely what produces the myth.
The One Place Where Earning More Is Taxed Less
There is a genuine oddity in the US system, and it goes the opposite way to what people expect.
Social Security stops at the wage base. Below it you pay 6.2% Social Security plus 1.45% Medicare on top of your income tax bracket. Above it, only Medicare continues.
| Gross | Bracket | Marginal rate with FICA |
|---|---|---|
| $50,000 | 12% | 19.65% |
| $100,000 | 22% | 29.65% |
| $200,000 | 24% | 26.35% |
At $200,000 the marginal rate is lower than at $100,000, despite being in a higher income tax bracket, because Social Security has stopped. A raise there is worth more per dollar than the same raise further down.
Effective Against Marginal
Two rates, answering different questions.
Effective is total tax divided by total pay — 21.26% in the example. It describes your overall position.
Marginal is what applies to the next dollar — 29.65% with FICA. It governs every decision about extra income: a raise, a bonus, overtime, a side job.
If you are working out whether extra work is worth it and you use your effective rate, you will consistently overestimate what you keep.
What a 401(k) Contribution Saves
Your bracket rate, on every dollar.
In the 22% bracket, $1,000 into a 401(k) reduces federal income tax by $220, so the contribution costs $780 of take-home.
One detail worth knowing: pre-tax retirement contributions reduce income tax but not FICA. Social Security and Medicare are charged on gross wages, so the saving is the bracket rate rather than the full marginal rate.
What Is Not Included
State income tax, and it is not a rounding error. Nine states charge none at all; others reach double digits. At the same salary, state tax can move take-home by several thousand dollars.
Also outside this calculation: itemised deductions above the standard deduction, tax credits, the Alternative Minimum Tax, self-employment tax, and any income that is not wages.
Filing Status Is Not a Small Detail
Married filing jointly does not simply halve the tax. The brackets are wider at every level, so the same household income is taxed less than it would be split across two single filers in the same bands:
$200,000 taxable, single: more federal tax
$200,000 taxable, married: lessThe standard deduction doubles too, from $15,000 to $30,000, which takes a further $15,000 out of tax entirely.
Where this matters most is comparing a household on one income against a household on two. Two people each earning $100,000 are taxed quite differently from one person earning $200,000, and the gap runs in the direction of the couple.
Pre-Tax Contributions Are the Main Lever
Of everything on this page, the contribution field is the only one you control.
Every dollar into a 401(k) or HSA comes off taxable income, so it saves your bracket rate immediately. In the 22% bracket that is 22 cents on the dollar; in the 32% bracket it is 32 cents. The higher your bracket, the more each contribution is worth — which is the opposite of how most people describe it.
An HSA is the unusual one: contributions are deductible, growth is untaxed, and qualified withdrawals are untaxed. Nothing else in the system does all three.
Understanding Your Result
Take-home is annual and monthly.
Federal tax and FICA separates the two.
By bracket shows exactly how much income fell into each band — which is what makes the marginal structure visible rather than theoretical.
Effective and marginal gives all three relevant rates.
Worth knowing flags the wage base, the bracket rate, or the state tax caveat.
When Should You Use This Calculator?
Before turning down a raise. It cannot cost you money.
To decide a 401(k) contribution. The bracket rate is the saving.
When comparing offers across states. Add state tax separately.
To understand a paycheck. If the deductions do not reconcile, ask.
Common Mistakes
Believing the bracket myth. A raise always leaves you with more.
Applying your bracket to your whole income. Only the top slice is taxed at that rate.
Using the effective rate to judge a bonus. Bonuses are marginal.
Forgetting FICA. It is 7.65% below the wage base and easy to leave out.
Forgetting state tax. It can be the largest remaining variable.
Assuming pre-tax contributions save the full marginal rate. They save the income tax bracket, not FICA.
Thresholds change every tax year and state tax is not included. Every figure here is an estimate for planning, not tax advice.