Bonus Tax Calculator (Supplemental Wage Withholding)
Estimate the tax withheld from a bonus with the 22% flat rate or the aggregate method.
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How to do it
- 1Step 1: Open Bonus Tax Calculator (Supplemental Wage Withholding) and add your input
Type your numbers or text, add your file, or pick the options you need. Nothing is uploaded: everything stays in your browser.
- 2Step 2: What Bonus Tax Calculator (Supplemental Wage Withholding) does
Estimate the tax withheld from a bonus with the 22% flat rate or the aggregate method.
- 3Step 3: Read the result and compare
The result appears at once. Change one value to see how the answer moves, then keep the figure that fits your case.
- 4Step 4: Copy or save it
Copy the result or download it. For an important decision, confirm it with the official source or an adviser.
About this tool
Enter your bonus, your regular paycheck and how often you are paid. The calculator shows federal withholding under both IRS methods, the Social Security and Medicare tax on the bonus, state tax at the rate you give and the net amount you receive.
Two methods
The percentage (flat) method withholds 22% of a bonus, and 37% on supplemental wages above $1 million in the year. In the aggregate method the bonus is added to a regular paycheck, tax is figured as if that larger paycheck repeated all year, and the tax on the regular paycheck alone is subtracted. Employers may choose either.
Withholding is not the final tax
The bonus is taxed at your real rate when you file your return. If 22% is more than your marginal rate you get the difference back; if you are in a higher bracket you may owe more.
FICA
Social Security tax of 6.2% applies up to the wage base ($184,500 in 2026, $176,100 in 2025), Medicare tax is 1.45%, and 0.9% extra applies to wages above $200,000 (single).
Worked example
A $10,000 bonus in 2026 for a single worker paid $4,000 twice a month, with 5% state tax: flat withholding is $2,200, the aggregate method gives about $2,852, FICA is $765 and state tax $500, so you take home about $6,535 under the flat method or $5,883 under the aggregate method.
Tips for best results
Check every box before you rely on a result, because one wrong digit changes the whole answer. Use the exact figures from your payslip, bill, certificate or contract, and keep a note of the date you calculated. Rates, thresholds and rules change from time to time, so for tax, fees and legal matters treat the output as an estimate and confirm with the official source named on this page. You can run as many scenarios as you like; nothing is saved or sent, and refreshing the page clears the boxes.
Quick facts
- Category: UK & US
- Works in your browser, no sign-up, no upload.
- Your input stays on your device.
- Available in English.
- Content last reviewed:
Frequently asked questions
Why is my bonus taxed more than my salary?
Mostly it is not: it is only withheld at a flat 22% or by the aggregate method. Your real tax is settled on your return.
Which method does my employer use?
Either one. The tool shows both so you can match your payslip.
Is there a different rate for very large bonuses?
Yes, 37% on supplemental wages above $1 million in a year. Enter what you have already received in the year.
Does it include 401(k) deferrals from the bonus?
No. If you defer part of the bonus, reduce the bonus amount you enter.