Read the bonus statement before doing the math
A bonus can look heavily taxed because the bank deposit combines several different deductions. Find the gross bonus, federal income tax withheld, Social Security, Medicare, state or local deductions, and any retirement or benefit deductions. Divide each line by the gross bonus separately. Calling the entire difference federal tax makes it difficult to identify the actual cause.
Compare the bonus statement with an ordinary paycheck. A larger federal income tax line may reflect the employer’s withholding method. A larger retirement contribution may reflect a percentage election that applies to bonus pay. Neither observation, by itself, tells you your final annual federal income tax. Ask payroll for the method and the deduction detail rather than asking why a bonus has a special tax bracket. IRS Publication 15 (2026), sections 5, 6, 7 and 9.
Why employers may withhold different amounts
IRS Publication 15 describes supplemental wage withholding. When supplemental wages are separately identified and federal income tax was withheld from regular wages in the current or preceding calendar year, an employer can generally choose the flat 22% method or an aggregate method. If the payment is combined with regular pay without separately identifying the amounts, withholding is figured as a single regular payroll payment.
Under an aggregate method, payroll calculates withholding using combined pay and subtracts the regular-pay withholding as required. A one-time large payment can therefore produce a larger withholding amount than you expected from an ordinary check. That is a collection calculation, not a ruling that every dollar you earn has entered a new final tax band.
There is a separate rule for supplemental wages over $1 million during the calendar year: the portion above the threshold is subject to mandatory 37% federal income tax withholding. Related employers can matter to that threshold. The 22% figure is therefore neither a universal maximum nor a rate an employee can simply choose for any paycheck. IRS Publication 15 (2026), sections 5, 6, 7 and 9.
A $10,000 bonus: two different questions
Worked example
Assume a $10,000 cash bonus qualifies for flat supplemental withholding, the employee remains below the Social Security wage base, no Additional Medicare Tax applies, and there are no state, local, benefit or retirement deductions. Federal income tax withholding is $2,200. Employee Social Security is $620 and Medicare is $145. The illustrative deposit is $7,035: $10,000 minus $2,200 minus $620 minus $145.
Now ask the annual liability question. If every additional taxable dollar from this bonus falls in a 24% ordinary federal band, and deductions, credits and other tax systems do not change, the incremental federal income tax is $2,400. The $2,200 withholding leaves a $200 income-tax gap attributable to this simplified comparison. The $765 of payroll tax is separate; do not subtract it again from the income-tax gap.
If instead all those bonus dollars fall in a 12% band under the same narrow assumptions, the incremental federal income tax is $1,200, so $2,200 of withholding exceeds that incremental amount by $1,000. These are conditional examples, not complete tax returns or promises about refunds. Other income, payment timing and credit phaseouts can change the household result. IRS Publication 15 (2026), sections 5, 6, 7 and 9.
Why overwithholding does not guarantee a refund
Your return combines the whole year’s income, deductions, credits, taxes and payments. One bonus can be overwithheld while ordinary pay is underwithheld. A working spouse, investment income or another employer can also change the result. A refund is the final reconciliation of the relevant payments and tax, not the amount withheld from one particular bonus.
Conversely, a 22% withholding rate can be too low for a higher-earner’s incremental income tax. Large stock compensation or repeated commission payments can make that gap material. Use the latest pay statements and a complete annual projection before assuming that an employer has already collected enough. The existing estimated-tax safe-harbor guide explains a separate question: possible underpayment penalties, rather than whether a bonus deposit looks reasonable. IRS Tax Withholding Estimator.
Source: IRS Tax Withholding Estimator
What to do after the bonus arrives
First, confirm whether your displayed bonus is gross or net. Then ask payroll whether the payment used flat supplemental withholding or aggregation, and whether your retirement election applied. Keep the statement with your year-to-date totals. Use actual withholding already collected rather than estimating it from a bank deposit.
Next, run the IRS Tax Withholding Estimator with current pay statements for every relevant job and spouse. Include the bonus once, in the correct place, and distinguish recurring pay from one-time compensation. Follow the resulting W-4 recommendation as a complete set of settings. Changing a single field from an old form can defeat the intended adjustment.
Finally, inspect a subsequent ordinary paycheck. Confirm the updated W-4 was processed and that an unusual bonus-period withholding amount did not get mistaken for your ongoing deduction. Recheck after another material compensation change. The goal can be a small refund, a chosen buffer or another supported payment target; the useful first step is to understand the projection. IRS Tax Withholding Estimator. IRS Form W-4 (2026), pages 1–3.
Sources: IRS Tax Withholding Estimator · IRS Form W-4 (2026), pages 1–3
Use Afterax for the question it actually answers
Scope and limits
The bonus calculator compares modeled federal liability before and after a bonus, separates incremental income tax from payroll tax, and compares the income-tax component with modeled flat supplemental withholding. It does not reproduce an employer’s aggregate payroll tables, retirement elections, state taxes or exact bank deposit.
Use the federal refund tool for its supported payment reconciliation, entering only the payment categories it accepts. The broader income-tax calculator estimates liability and does not reconcile payments. Afterax keeps final 2025 values as the default and labels 2026 calculations as planning estimates. Select the year of payment deliberately; a planning result is not a completed return.
Common questions
Is every bonus withheld at 22%?
No. The flat method has conditions; aggregation and the over-$1-million rule can apply. Payroll taxes and other deductions remain separate.
Can my bonus move me into a higher bracket?
Some additional taxable income can reach a higher band. That does not reprice all lower taxable income at that rate.
Should I claim exempt to keep my bonus?
Only claim an exemption when you meet the W-4’s actual exemption conditions. Use an annual withholding projection to make an appropriate adjustment.
Sources
Primary references checked October 24, 2026.
- IRS Publication 15 (2026), sections 5, 6, 7 and 9IRS · Supplemental wages; Social Security and Medicare; withholding · accessed 2026-10-24
- IRS Tax Withholding EstimatorIRS · Who can use the estimator; what you need; results · accessed 2026-10-24
- IRS Form W-4 (2026), pages 1–3IRS · Steps 2–4 and general instructions · accessed 2026-10-24
Next steps
Compare incremental bonus tax
Compare incremental federal tax on a bonus with flat 22% withholding.
Reconcile supported federal payments
Reconcile named federal payments against a wage-only estimate, not your whole IRS refund.
Understand payment safe harbors
Read the current-year and prior-year payment targets that avoid estimated-tax penalties.