What is the IRS flat rate for bonus withholding?

For 2024, the IRS flat supplemental withholding rate is 22% for bonuses under $1 million. Bonuses exceeding $1 million in a year are withheld at 37% on the amount over $1 million. This flat rate applies only to federal income tax — FICA taxes are separate.

What is the aggregate method?

The aggregate method combines your bonus with your most recent regular paycheck, calculates federal income tax on the combined amount using your normal withholding rate, then subtracts the tax already withheld on the regular paycheck. The difference is the withholding on the bonus. This can result in more or less withholding than the flat rate depending on your bracket.

Do FICA taxes apply to bonuses?

Yes. Social Security (6.2% up to the $168,600 wage base in 2024) and Medicare (1.45%) apply to bonuses just like regular wages. If you have already reached the Social Security wage base for the year, no Social Security tax is withheld on the bonus.

Will my bonus be taxed at a higher rate than my salary?

Under the flat rate method, your bonus is withheld at exactly 22% regardless of your bracket. Under the aggregate method, the effective rate on the bonus reflects your marginal bracket. Either way, your bonus is included in total annual income and taxed at your actual marginal rates when you file — withholding is an estimate, not a final tax.

Why might I get a refund if too much is withheld on my bonus?

If your employer withholds more than your actual tax liability for the year, the excess is refunded when you file your tax return. The flat 22% rate may over-withhold for lower-bracket earners, resulting in a refund at filing.

Does this calculator include state taxes?

No. This tool covers federal withholding only. Many states also tax bonuses — some use a flat supplemental rate, others use the aggregate method. Check your state revenue department for state-specific rates.

Bonus Tax Calculator

Name: Bonus Tax Calculator
Availability: InStock
Author: Nham Vu

Estimate federal tax withheld on a bonus using the IRS 22% flat rate or the aggregate method, and see your take-home amount.

Bonus Details

Bonus Amount ($)

Filing Status

Regular Pay Frequency

Regular Gross Pay per Period ($) Required for aggregate method

Year-to-Date Wages So Far ($) Used to check Social Security wage base ($168,600)

Enter your bonus amount and click Calculate to see the withholding breakdown.

Summary

Estimate federal tax withheld on a bonus using the IRS 22% flat rate or the aggregate method, and see your take-home amount.

How it works

Enter your bonus amount and select your pay frequency.
Enter your regular gross pay per period and filing status.
Choose the flat rate (22%) or the aggregate method — or compare both.
The flat-rate method withholds exactly 22% federal income tax on the bonus.
The aggregate method combines the bonus with your regular pay, calculates withholding on the combined amount, then subtracts what was already withheld on regular pay.
FICA taxes (Social Security 6.2%, Medicare 1.45%) apply to both methods unless the Social Security wage base has been reached.

Use cases

Estimating your actual take-home amount before receiving a year-end bonus.
Comparing flat-rate vs aggregate withholding to understand which results in less withholding.
Planning personal finances around a performance bonus or signing bonus.
Verifying your employer used the correct IRS supplemental wage method.
Understanding why your bonus check was smaller than expected.
Calculating net bonus for budgeting or investing decisions.

Frequently Asked Questions

Last updated: 2026-06-11 · Reviewed by Nham Vu