Bonus paycheck calculator
When a bonus is paid as a separate payment from your regular wages, federal law gives your employer a flat-rate shortcut: 22% federal withholding on supplemental wages up to $1,000,000 in a calendar year, and 37% on the part above $1,000,000. Social Security and Medicare apply as usual — including the $184,500 Social Security wage base for 2026 and the 0.9% Additional Medicare Tax once wages pass $200,000. This page's headline number uses that separate-payment method.
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The other method: aggregated
Your employer may instead aggregate the bonus with your regular wages for the pay period and withhold as if the total were one regular paycheck, subtracting what was already withheld from the regular wages. To estimate that number, add the bonus to your gross pay on the main calculator for that one check — the difference between the two stubs is the aggregated withholding. Which method your employer uses is their choice (the flat rate is mandatory past $1,000,000); neither changes your final tax, only the prepayment.
State withholding on bonuses
States handle bonuses their own way — some apply a flat supplemental rate (Massachusetts, for example, withholds at its regular 5%/9% split), most simply tax the bonus as regular wages in the pay period. For a state estimate, run the bonus through your state's page as part of that check's gross pay. The 22% federal figure above is the one number that is the same in all 50 states.