Bonus Calculator

Work out a bonus as a fixed amount or a percentage of salary and prorate it for part of a year. Optionally, estimate the federal withholding on it using 2026 IRS and Social Security figures.

Free to use. No sign-up. Your figures stay in your browser.

The bonus

Your result

Enter your figures and select Calculate. Your result appears here.

How to use this calculator

Choose whether the bonus is a percentage of salary or a fixed amount, and enter the figures.
If the employee was only eligible for part of the year, tick Prorate and enter the months.
To estimate withholding, tick Estimate 2026 federal withholding. Add wages already paid this year if the employee is a high earner.
Select Calculate.

How it works

Gross bonus

Bonus = salary × bonus % ÷ 100 (or the fixed amount)

Prorated bonus = bonus × months eligible ÷ 12

Estimated federal withholding (optional)

The IRS treats bonuses as supplemental wages. When a bonus is paid separately from regular wages, or identified separately on the same paycheck, employers may withhold federal income tax at a flat 22%. Supplemental wages above $1 million in a calendar year must be withheld at 37%. Bonuses are also subject to Social Security and Medicare taxes.

Item	2026 rate	Applies to
Federal income tax (flat-rate method)	22%	Supplemental wages up to $1 million in the year
Federal income tax (mandatory rate)	37%	Supplemental wages over $1 million in the year
Social Security (employee share)	6.2%	Wages up to $184,500 in the year
Medicare (employee share)	1.45%	All wages
Additional Medicare Tax	0.9%	Wages over $200,000 in the year

Employers can instead use the aggregate method, which combines the bonus with regular wages and uses the employee's Form W-4 and the normal withholding tables. That can give a different figure. Withholding is a prepayment, not the final tax bill: the employee's actual federal income tax is worked out on their tax return.

Worked example

An employer pays a 10% bonus on a $70,000 salary. The employee joined in April, so they're eligible for 9 months. They have been paid $50,000 so far in 2026.

Step	Result
Full bonus: $70,000 × 10%	$7,000.00
Prorated: $7,000 × 9 ÷ 12	$5,250.00
Federal income tax: $5,250 × 22%	$1,155.00
Social Security: $5,250 × 6.2%	$325.50
Medicare: $5,250 × 1.45%	$76.13
Estimated take-home before state and local tax	$3,693.37

Frequently asked questions

Are bonuses taxed more than regular pay?

No. A bonus is taxed as ordinary income, like the rest of your pay. What can differ is how much is withheld from the bonus check. If your employer uses the flat 22% rate, more or less may be withheld than your actual tax rate, and the difference is settled when you file your return.

Why 22%?

IRS Publication 15 sets 22% as the optional flat withholding rate for supplemental wages such as bonuses and commissions, when they're paid separately or identified separately from regular wages. A mandatory 37% rate applies to supplemental wages over $1 million paid to an employee during the calendar year.

Do Social Security and Medicare apply to bonuses?

Yes. In 2026, Social Security is 6.2% of wages up to $184,500 for the year, and Medicare is 1.45% of all wages. If the employee's wages for the year pass $200,000, the employer also withholds 0.9% Additional Medicare Tax on the amount above $200,000. Enter wages already paid this year so the calculator can apply these limits.

Are state taxes included?

No. State and local income tax withholding on bonuses varies by state. Some states use their own flat supplemental rate, and some have no income tax. Check your state tax agency for its rules.

Does a bonus affect overtime pay?

It can. For nonexempt employees, the regular rate used to work out overtime includes most pay for employment, including many nondiscretionary bonuses. The Department of Labor's Fact Sheet #23 explains the regular rate.

How do I prorate a bonus?

Multiply the full bonus by the months the employee was eligible and divide by 12. A $6,000 bonus for 8 months is $6,000 × 8 ÷ 12 = $4,000. Your bonus plan may define eligibility differently, for example by days, so follow its terms.

Sources

The bonus itself is simple arithmetic. The optional withholding estimate uses these official 2026 figures, which are stored in one place in the calculator so they can be updated each year.

IRS Publication 15 (2026), Employer's Tax Guide, section 7: Supplemental Wages. Bonuses and commissions are supplemental wages. The optional flat withholding rate is 22%, and 37% applies to supplemental wages over $1 million in a calendar year.
Social Security Administration: Contribution and benefit base. 2026 Social Security wage base of $184,500; tax rates of 6.2% (Social Security) and 1.45% (Medicare) each for employees and employers.
IRS Topic 560: Additional Medicare Tax. Employers withhold an extra 0.9% Medicare tax on wages paid to an employee above $200,000 in a calendar year.
IRS Topic 751: Social Security and Medicare Withholding Rates. Employee and employer Social Security and Medicare rates.
U.S. Department of Labor: Fact Sheet #23, overtime pay requirements. Explains that the regular rate used for overtime includes all pay for employment, except certain payments the law excludes.

Last reviewed: October 2, 2026. This tool is not an official government calculator, and it is not tax, legal or financial advice. See the resources disclaimer.

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