Tools/Income & self-employment/Bonus Tax Calculator✓ CHECKED AGAINST WORKED EXAMPLES · SEP 29, 2026

How much of my bonus will I keep?

See what your bonus check will show, what the bonus really costs in tax once you file, and what putting part of it in your 401(k) changes.

Edit on my map

Bonus, severance or vest before tax$The gross amount. The starting figure is an example, not your bonus.Your pay for the year, before this bonus$Prefilled from your Money Map. Salary and other W-2 pay before any 401(k) deferral. Add your spouse’s pay if you file jointly.Pre-tax 401(k) contributions from your pay this year$Prefilled from your Money Map. The 2026 limit is $24,500 before catch-up contributions.State income tax rate%Optional. Your state’s rate on this income; 0 leaves state tax out. States withhold on bonuses by their own rules.Bonuses and vests already paid this year$Supplemental pay counts toward the $1 million above which withholding rises to 37%. Usually 0.

Share of the bonus you put in your 401(k)

The whole bonus is paid to you.

Filing status

YOU KEEP FROM THE BONUSUNDER-WITHHELD

$6,835

Of a $10,000 bonus, your check shows $7,035: $2,200 of federal income tax is withheld at the flat 22% supplemental rate and $765 goes to Social Security and Medicare. The bonus really adds $2,400, so you would owe $200 more when you file. After filing you keep $6,835 in cash (68% of the bonus).

Your check

$7,035

Withheld

$2,200

Really owed

$2,400

Payroll tax

$765

UNDERSTAND YOUR RESULT

LIBRARY CHAPTERReading Your Paycheck, From Gross to NetEvery line on a pay stub, which deductions you control, what pre-tax saving does to your tax, how to capture the full employer match, and how to set withholding so tax time holds no surprise.LIBRARY CHAPTERYour Paycheck: Withholding and the W-4 for NonresidentsHow gross pay becomes take-home pay on a visa, the special Form W-4 instructions for nonresident aliens, why employers add to a nonresident's wages before withholding, treaty exemptions on Form 8233, and how a 401(k) changes the tax.

Terms:Tax withholding

Where a bonus goes

Of $10,000, $2,400 to federal income tax, $765 to Social Security and Medicare, leaving $6,835 in cash.

The bonus check against what you keep after filing

	On the check	After you file
Bonus	$10,000	$10,000
Federal income tax	−$2,200	−$2,400
Social Security + Medicare	−$765	−$765
Cash in hand	$7,035	$6,835

The check pays $7,035; once the return is filed the same bonus leaves $6,835, $200 less because the flat rate is below the 24% bracket the bonus lands in.

Share of a bonus you keep at different sizes

$5k$3,418 in cash

68%

$10k$6,835 in cash

68%

$25k$17,088 in cash

68%

$50k$34,826 in cash

70%

$100k$69,874 in cash

70%

$250k$164,799 in cash

66%

On $145,000 of pay you keep 68% of a $5,000 bonus and 66% of a $250,000 one, because a bigger bonus reaches higher brackets; yours is highlighted.

What moves the needle

Each row re-runs the calculation with one change. Click to apply.

How it's computed

FORMULA

Withheld = 22% × (bonus − 401(k) deferral) up to $1,000,000 of supplemental pay in the year + 37% × the rest

Really owed = tax on (pay − 401(k) + bonus − deferral − standard deduction) − tax on (pay − 401(k) − standard deduction)

Payroll tax = Social Security 6.2% (to $184,500 of wages) + Medicare 1.45% (+ 0.9% above the threshold) on the whole bonus, deferral included

Cash kept = bonus − deferral − really owed − payroll tax − state tax; the check pays the same with withheld in place of really owed

The bonus is ordinary income, the last income of the year, stacked on top of your pay, so it is taxed at the highest brackets your pay leaves. Federal income tax uses the 2026 brackets and the standard deduction for single filers; other income, credits and deductions are not included.
Your employer withholds at the flat supplemental rate whatever your bracket (22%, and 37% above $1 million of supplemental pay in the year). Some employers instead add the bonus to a regular paycheck and withhold on the total; that changes the withholding, not the tax you really owe, and is not modelled.
A 401(k) deferral taken from the bonus lowers the income the withholding and the tax apply to, but Social Security and Medicare tax still apply to it. It is capped by the room left under the 2026 limit of $24,500 after what you have already deferred from pay; catch-up contributions are not included.
Social Security tax stops at $184,500 of wages in 2026; Medicare tax has no cap, and an extra 0.9% applies to wages above $200,000 (the threshold for the tax you owe is $250,000 on a joint return). Employers withhold these correctly.
State and local income taxes are not modelled. The optional state rate shows what a flat rate would take from the part you do not defer.

WORKED EXAMPLE · SAMPLE NUMBERS

Check: $10,000 − $2,200 federal withholding − $765 Social Security and Medicare = $7,035. Really owed: the extra federal tax of $2,400 (last dollar in the 24% bracket), so the gap is $2,400 − $2,200 = $200. You keep $6,835.

SOURCES

[1]Publication 15 (Circular E), Employer’s Tax Guide (2026), section 7: Supplemental WagesInternal Revenue Service [2]Rev. Proc. 2025-32: 2026 inflation-adjusted tax items (brackets, standard deduction)Internal Revenue Service, 2025 [3]Topic no. 751, Social Security and Medicare withholding ratesInternal Revenue Service [4]Topic no. 560, Additional Medicare TaxInternal Revenue Service [5]401(k) limit increases to $24,500 for 2026, IRA limit increases to $7,500Internal Revenue Service news release, November 2025 [6]Tax Withholding EstimatorInternal Revenue Service

HSBuilt by Hussain Sehorewala · checked against worked examples · Sep 29, 2026

Keep this number honest as your life changes.

Put it on your Money Map and it re-runs as you change the seven numbers. It stays in this browser, and the calculator stays free.

Open your Money Map Tell me when bank sync opens

Questions about this result

Employers may withhold federal income tax on supplemental pay, which includes bonuses, at a flat rate instead of using your bracket. For 2026 that rate is 22%, and 37% on supplemental pay above $1 million in a year (IRS Publication 15). It is a withholding rule, not the tax you finally owe.

No. A bonus is taxed at the same rates as the rest of your income; it only looks heavier because the extra income lands in your top bracket and the flat 22% is withheld from it. The difference between what was withheld and what you really owe is settled when you file, as a bill or a refund.

On the example of $145,000 of pay with $4,350 already put in a 401(k), filing single, you keep $6,835: $2,400 goes to federal income tax (the bonus lands in the 24% bracket) and $765 to Social Security and Medicare. The check shows $7,035, because only $2,200 is withheld, so you would owe about $200 more when you file. State tax would take more.

Yes for income tax. Money you defer into a 401(k) is not taxed as income now, so it is not in the check and not in the withholding, but Social Security and Medicare tax still apply to it. The 2026 limit is $24,500 before catch-up contributions, counting what you have already put in from your pay.

It can be. If your pay leaves room in the 10% or 12% brackets, the bonus is taxed there first and 22% is more than you owe, so you get the difference back as a refund. The bracket the bonus lands in, shown above, decides it.

Mostly yes. Vested RSUs and severance pay are supplemental wages with the same 22% withholding and the same real tax, so the figures apply. The RSU page adds the bracket-by-bracket view and larger vest sizes.

Many states withhold at their own flat rate on supplemental pay, and the rate can differ from what you finally owe. This page leaves state tax out unless you enter a flat rate, which then shows what it would take.

THE LEDGER · 25 minBuilding Passive Income to 20% of Your Total: The Proven System

YOUR MAP · 0 of 7 doneNext: FIRE CalculatorContinue →