Bonus Tax Withholding Calculator
Bonuses are taxed at the supplemental federal rate: 22% on amounts up to $1M, 37% above. Your real tax bracket may be higher or lower — calculate the difference and your potential refund or shortfall.
| Federal supplemental withholding | — |
| Social Security 6.2% | — |
| Medicare 1.45% + Additional Medicare 0.9% if >$200K | — |
| State withholding | — |
| Total tax withheld | — |
| Net bonus to your bank | — |
| Real federal tax (using your bracket) | |
| Real federal tax on bonus | — |
| Over/under-withheld | — |
Federal withholding on bonuses uses the 'supplemental' method: 22% flat on amounts up to $1M aggregate per year, then 37% above. This is statutory withholding — it has nothing to do with your real tax bracket, which means high earners often see a tax bill at year-end because 22% under-withholds the real 32-37% rate.
Two Withholding Methods
Employers can use (1) the supplemental method: 22% flat on bonus, separately from regular paycheck, or (2) the aggregate method: add bonus to your current paycheck and withhold based on the combined annualized rate. Aggregate is more accurate but rarely used because it's harder to administer. Most employers use 22% supplemental.
The $1M Threshold
When YTD supplemental wages (bonuses, commissions, severance, retroactive pay) exceed $1M, withholding jumps to 37% on the excess. This is mandatory — employer must use 37% regardless of your real bracket. Often produces large refunds for ultra-high earners.
Avoid Year-End Surprise
If your salary puts you in the 32-37% federal bracket, the 22% supplemental rate UNDER-withholds. Solutions: (1) increase your W-4 line 4(c) withholding to compensate, (2) make a Q4 estimated tax payment via IRS Direct Pay, or (3) ask payroll to use the aggregate method.
Last updated May 2026. Sources: IRS Pub 15 Employer Tax Guide, IRS Pub 15-T Withholding Methods, IRS Form W-4.