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Your bonus isn't taxed higher. It's withheld higher — and the method matters.
The shock of a bonus check missing a third of its value is withholding, not tax — and there are two completely different ways payroll computes it. A separate bonus check gets the flat 22% federal supplemental rate. A bonus folded into your regular check gets the aggregate method: the whole check is treated as if you earn it every pay period, annualized through the 2026 brackets, and divided back — so one big commission check annualizes into the 32–35% brackets and gets withheld like you make half a million. This calculator runs both methods side by side and compares them to your TRUE liability: the bonus stacked at your actual marginal brackets.
Bonus recipients confused by a shrunken bonus check use it to separate the 22% flat withholding from their true marginal liability — and to know whether April brings money back.
No. Bonuses are ordinary income taxed at your regular marginal brackets. They only LOOK overtaxed because of withholding method. Two possibilities (IRS Pub. 15-T): a separate supplemental check gets flat 22% federal (37% above $1M); a bonus combined with regular pay gets the aggregate method — the combined check is annualized (multiplied by your pay periods), taxed at those brackets, and divided back. A $13,000 commission check withheld by aggregate looks like a $338,000 salary to the withholding tables — that's how a modest earner sees 24%+ withheld on one check.
Flat 22% method: when your salary plus bonus puts top dollars in the 24%+ brackets — roughly above $105,700 taxable for single filers in 2026. Aggregate method: almost never — it over-withholds for everyone whose real annual income is below what the big check annualizes to, and the excess comes back as a refund. If your income is lumpy (commissions, overtime spikes), expect each big check to be over-withheld and plan cash flow around the refund, or adjust your W-4 to compensate.
The cleanest lever: increase your pre-tax 401(k) contribution for the bonus paycheck — every dollar deferred dodges your marginal rate (22% or 24% for most bonus recipients) plus state tax, and pre-tax deferrals also shrink the wage base the aggregate method annualizes. An HSA contribution works the same way if you are eligible. What does NOT work: asking payroll to withhold less on the check itself — withholding method is their choice, not yours. You fix the total at filing or through your regular W-4.