How are bonuses taxed?

A bonus paid on its own is a supplemental wage payment, and payroll runs it through a different door than your salary. Your employer may withhold federal income tax on it at a flat 22%, ignoring your W-4 entirely. On the $10,000 bonus above, that is $2,200. Social Security takes $620 and Medicare takes $145, both at their ordinary rates, so $2,965 leaves the check and $7,035 arrives. That is 29.6% of the payment gone, before any state tax.

None of that is a rate anyone decided your bonus deserves. The flat rate is set by regulation at the third lowest rate in the individual rate table, which for 2025 is 22%. It applies to a bonus of $10,000 and to a bonus of $1,000,000 identically, and it applies whether you file single or jointly, whether you earn $30,000 or $300,000. A rate that does not look at any of those things is not measuring your tax. It is collecting a deposit against it.

To find what the bonus actually costs, you have to run the return. This calculator runs it twice: once on $60,000 of wages and once on $70,000, and takes the difference on line 22, the federal income tax after credits. Without the bonus the tax is $5,075. With it, $6,855. The bonus adds $1,780, which is 17.8% of it.

So $2,200 was withheld against $1,780 of real tax, and $420 comes back when you file. Nothing about the bonus was taxed at a special rate. It was stacked on top of the salary you already had, taxed in the brackets that came next, and the deposit turned out to be too large. That is the entire story, and it is the reason the two numbers at the top of this page are printed at the same size.

Social Security and Medicare do not participate in the settlement. They are withheld at exactly what they cost, $765 here, and the return does not revisit them. So when the check looks like it lost 29.6%, only the income tax part is ever coming back.

Whether the flat rate over-collects or under-collects depends entirely on the salary the bonus lands on, which is the thing the flat rate cannot see. This table holds the bonus at $10,000 and the status at single, and changes only the salary underneath it. Every row is two complete returns, not a bracket applied to a number.

The withheld column never moves. The one next to it moves from 12.0% to 35.0%. At $30,000 the flat rate takes nearly twice what the bonus costs, so $1,000 comes back. At $90,000 the two happen to match almost exactly and nothing settles either way. At $300,000 the bonus costs $3,500 against $2,200 withheld, so $1,300 is still due in April. Anyone earning well is being under-withheld on their bonus, not over-taxed on it, which is the opposite of the complaint.

Once your supplemental wages for the calendar year pass $1,000,000, the part above that line must be withheld at 37%, the top individual rate. The employer has no choice about it and no election can lower it. Take a $1,500,000 bonus on a $300,000 salary, filing single: the first $1,000,000 is withheld at 22.0% and the remaining $500,000 at 37%, which comes to $405,000 of federal income tax withheld.

The bonus adds $548,158 of federal income tax to the return. Even at the mandatory rate the withholding is $143,158 short, because the flat 22.0% on the first $1,000,000 sits far below the bracket that money is actually taxed in. If you are in this position, the check is not the surprise. April is. The advanced inputs above take the supplemental wages you have already been paid this year, so a second bonus is split at the right point rather than starting the clock over.

A bonus can cost more than the income tax on it, in two ways this calculator computes and most do not. The first is credits. At $12,000 of salary, a $4,000 bonus filing single adds only $26 of federal income tax, but it also pushes you down the earned income credit phase-out and costs $306 of credit. The real federal cost of that bonus is $638, not $26. Withholding took $880, so $548 still comes back, but the bonus was worth meaningfully less than the check suggested.

The second is Additional Medicare Tax, and it runs the other way. Employers must withhold an extra 0.9% on wages above $200,000 no matter how you file, but the return only charges it above $250,000 if you are married filing jointly. A $100,000 bonus on a $150,000 salary filing married filing jointly has $450 of it withheld and owes $0 of it on the return, so Form 8959 credits the whole $450 back. That is a mismatch built into the law, not an error in your payroll.

State and local tax. Most states run their own supplemental withholding rate on bonuses, a few charge nothing, and a handful will take more from the bonus than the federal government does. None of it is on this page, and it comes out of the same check.

Anything about you that is not salary, bonus, and filing status. Dependents and the credits they carry, itemized deductions, a working spouse, self-employment or investment income, and money your employer deferred out of the bonus into a 401(k) or an HSA all change what the bonus costs. The two returns behind the answer assume one earner, wage income only, the standard deduction, and no dependents, which is why the joint numbers here describe a single-earner household rather than two salaries.

The flat rate itself has a condition. Your employer may only use it if income tax was withheld from your regular wages this year or last; otherwise the bonus goes through the ordinary W-4 tables and the withheld figure on this page will not match your check. And the parameter set is tax year 2025 only, current rates rather than a history of past ones. Everything here is federal, it is a model of your return rather than your return, and none of it is tax advice.

This calculator is built to be used without a browser. Every input is a query parameter on this page, and the same parameters on the JSON twin return the complete answer as a document.

GET /tools/bonus-tax.json?salary=250000&bonus=50000&status=married-joint

The response carries inputs after parsing and clamping, result with the withholding on the bonus split into its flat and mandatory parts alongside Social Security, Medicare, and Additional Medicare Tax; the federal tax the bonus actually adds, split into income tax, Additional Medicare Tax, any credit lost, and payroll tax; what lands in the account and what settles at filing; both withoutBonus and withBonus Form 1040 snapshots the difference was taken from; plus drivers, and sensitivity across a salary ladder and across every filing status, drivers ranked by effect with a plain sentence each, assumptions that say for every field whether you supplied it and name the source when the default came from one, sources with a URL and an as-of date for each source the tool cites, which is an empty list on the calculators whose every default is an example input rather than a published figure, warnings, a disclaimer, and in tool the canonicalUrl and jsonUrl that carry only your non-default parameters. The canonical URL is the answer's permanent address; use it when you cite the number.

Parameters, all optional, in any order:

• salary ($ per year), default $60,000 per year.
• bonus ($), default $10,000.
• rate (%), default 22%, from 26 CFR 31.3402(g)-1 (supplemental wage payments).
• paid ($), default $0.
• status (one of single, married-joint, head-of-household), default single.

Values accept plain numbers and loose human formats such as 100k, $100,000, or 6.5%. Unknown parameters are ignored, values outside a field's range are clamped and reported in warnings, and the endpoint never fails on bad input. Responses are cacheable for a day; the defaults change when their sources publish, and tool.version changes when the method does.

• 26 CFR 31.3402(g)-1 (supplemental wage payments), as of 2025-01-01. The regulation that lets an employer withhold on a separately paid bonus at one flat rate instead of running it through the wage tables. The rate is the third lowest rate under section 1(c), 22% for 2025, and it is available only if income tax was withheld from your regular wages this year or last.
• 26 U.S.C. § 3402(g)(1)(A), as of 2025-01-01. The statute requiring withholding at the highest rate under section 1, 37% for 2025, on supplemental wages above 1,000,000 dollars for the calendar year. This one is mandatory, not optional.
• IRS Publication 15 (Circular E), section 7, as of 2025-01-01. The employer instructions for supplemental wages: when the flat rate may be used, when the aggregate method applies instead, and the Additional Medicare Tax an employer must withhold once your wages pass $200,000 for the year regardless of how you file.
• IRS Rev. Proc. 2024-40 (2025 inflation-adjusted items), as of 2025-01-01. The rate tables and standard deduction for tax year 2025, which are what decide the real tax on the bonus once it is stacked on your salary.
• One Big Beautiful Bill Act (P.L. 119-21), as of 2025-07-04. The statute that sets the current standard deduction used for 2025.
• 26 U.S.C. (Internal Revenue Code), as of 2025-01-01. The code sections the liability half implements: § 1 rates, § 63 deduction, § 32 earned income credit, § 3101 and § 3121 payroll tax, § 3101(b)(2) Additional Medicare Tax.

The return figures come from the same rate tables, standard deduction, and credit amounts the engine reports for every computation. The withholding rates are the one thing on this page the return engine does not produce: a return does not model payroll, so the 22% flat rate and the 37% rate above $1,000,000 are read from the regulation and the statute that set them, with the dates they were checked.

Carlo is a personal finance agent. It knows your accounts, debts, and goals, so instead of a worked example it can see the bonus land, know what was withheld against it, and tell you in March whether April is a refund or a bill. Text it the question.

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