Withholding & Planning · 2026
Bonus Tax Calculator
Your bonus isn't taxed at 22% — it's withheld at 22%. Enter your salary and bonus to see exactly what comes out of the check under IRS Publication 15 supplemental wage rules, what the bonus actually adds to your tax bill bracket by bracket, and the difference you'll settle at filing time.
Your bonus
Gross annual pay before the bonus — used to find your real marginal rate
Bonus, commission, severance, or other supplemental wages paid separately
Only used for the aggregate-method comparison
Chart legend
Informational only — not professional tax advice.
Enter your salary and bonus to see what comes out of the bonus check — and how that compares to the tax the bonus actually adds. The flat 22% withholding rate is not your tax rate.
Methodology
Withholding vs. actual tax — the distinction this tool exists to show
Withholding is an advance payment collected when the bonus is paid; actual tax is determined by your marginal brackets when you file. The two are computed by entirely different rules, which is why they rarely match. This calculator computes both and shows the difference — the amount that will move your refund or balance due at filing.
What comes out of the check (percentage method)
When a bonus is paid separately from regular wages, IRS Publication 15 (Section 7, Supplemental Wages) permits withholding federal income tax at a flat 22% on supplemental wages up to $1,000,000 for the year. Withholding at 37% — the highest income tax rate — is mandatory on any portion of cumulative supplemental wages above $1,000,000, regardless of your Form W-4. The bonus is also subject to employee FICA: Social Security at 6.2% on wages up to the 2026 wage base of $184,500, Medicare at 1.45% on all wages, and Additional Medicare withholding of 0.9% on wages an employer pays you beyond $200,000 in the year (IRC §3102(f) — this employer threshold is flat, not filing-status dependent).
The aggregate method comparison
Publication 15 alternatively allows the aggregate method: the bonus is added to the regular wages for the current pay period, withholding is computed on the combined payment using the Publication 15-T Percentage Method (the same computation as our W-4 Withholding Estimator, assuming a default W-4 with no Steps 2–4 entries), and the withholding attributable to the bonus is the combined amount minus the withholding on regular wages alone. Because Publication 15-T annualizes each payment, a large bonus is withheld as if it recurred every pay period — the source of many "half my bonus disappeared" surprises.
What the bonus actually costs
The actual federal income tax the bonus adds is computed by running the 2026 bracket schedule twice — once on salary alone, once on salary plus bonus, both with the standard deduction — and taking the difference. The bracket-stacking chart shows where the bonus dollars land: salary fills each bracket first (green), bonus dollars stack on top (amber). Actual FICA is computed the same way, using your filing-status threshold for the Additional Medicare Tax; when that differs from the flat $200,000 employer withholding threshold, the tool shows the Form 8959 reconciliation amount.
Formula
Percentage-method withholding: fed_withheld = 0.22 × min(bonus, 1,000,000) + 0.37 × max(0, bonus − 1,000,000) ss_withheld = 6.2% × [min(salary + bonus, 184,500) − min(salary, 184,500)] medicare = 1.45% × bonus addl_medicare = 0.9% × [max(0, salary + bonus − 200,000) − max(0, salary − 200,000)] total_withheld = fed_withheld + ss_withheld + medicare + addl_medicare Actual tax added by the bonus: fed_actual = tax(salary + bonus) − tax(salary) [2026 brackets, standard deduction] fica_actual = FICA(salary + bonus) − FICA(salary) [filing-status Additional Medicare threshold] Difference at filing = total_withheld − (fed_actual + fica_actual) > 0 → over-withheld (moves the return toward a refund) < 0 → under-withheld (adds to the balance due)
Tax year scope and sources
Supplemental wage withholding rules: IRS Publication 15 (2026), Section 7 — Supplemental Wages; flat-rate withholding regulation: 26 CFR §31.3402(g)-1. Aggregate-method tables: IRS Publication 15-T (2026) Percentage Method. 2026 brackets and standard deductions: IRS Rev. Proc. 2025-32. Social Security wage base: SSA 2026 COLA Fact Sheet. Additional Medicare Tax withholding and reconciliation: IRC §3102(f) and Form 8959 instructions.
Stated assumptions and limitations
- State income tax not included. Most states also withhold on bonuses, many at their own flat supplemental rates, which this tool does not model. Use the state income tax calculators to estimate the state-side liability the bonus adds.
- Single supplemental payment assumed. The $1,000,000 mandatory-37% threshold applies to cumulative supplemental wages for the year. If you received earlier bonuses or commissions this year, the threshold may be reached sooner than shown.
- One employer assumed. The Social Security wage base and the $200,000 Additional Medicare withholding threshold are applied against your salary and bonus combined, as if paid by one employer with salary paid first.
- Standard deduction, wage income only. The actual-tax side applies the standard deduction and treats salary plus bonus as your total income. Other income, itemized deductions, and credits will change the marginal rate the bonus actually faces.
- Default W-4 for the aggregate comparison. The aggregate-method figure assumes a Form W-4 with no Step 2 checkbox and no Step 3–4 entries. Your actual W-4 elections change that number (the percentage-method flat rate ignores the W-4 entirely).
- Pre-tax deductions not modeled. 401(k) or other pre-tax contributions withheld from the bonus check reduce both the withholding base and take-home shown here.
Last reviewed: July 2026. Supplemental rates, the wage base, and brackets are updated annually after the IRS publishes the revised Publication 15/15-T (typically January) and Rev. Proc. bracket adjustments (typically October or November).
Frequently asked questions
Is my bonus really taxed at a higher rate than my salary?
No — this is the most common bonus misconception. Bonuses are withheld differently, not taxed differently. When your employer pays a bonus separately from regular wages, IRS Publication 15 lets them withhold federal income tax at a flat 22% (the percentage method). But at filing time, your bonus is just ordinary income: it's added to your salary and taxed through the same brackets as everything else. If your marginal rate is below 22%, the extra withholding comes back as a refund. If your marginal rate is above 22%, you were under-withheld and will owe the difference. The calculator shows both numbers side by side so you can see exactly which situation you're in.
What's the difference between the percentage method and the aggregate method?
IRS Publication 15 gives employers two ways to withhold on supplemental wages paid alongside regular wages. The percentage method withholds a flat 22% on the bonus (mandatory 37% on any portion of cumulative supplemental wages over $1 million) — simple and predictable, and the method most large employers use for separately-paid bonuses. The aggregate method adds the bonus to your regular paycheck and computes withholding on the combined amount using the normal Publication 15-T tables, then subtracts what would have been withheld on the regular paycheck alone. Because those tables annualize each paycheck, a large bonus gets withheld as if you earned it every pay period — which is why the aggregate method often takes out dramatically more than 22%. Either way, your actual tax is the same; only the timing of when you settle up differs.
Why was more than 22% taken out of my bonus check?
Three common reasons. First, FICA: on top of the 22% federal income tax withholding, your bonus is subject to Social Security (6.2%, until your year-to-date wages reach the 2026 wage base of $184,500) and Medicare (1.45%, plus 0.9% Additional Medicare withholding once your wages from one employer pass $200,000) — that alone brings typical total withholding to just under 30%. Second, state income tax withholding, which this calculator doesn't model but most states require. Third, your employer may have used the aggregate method, which annualizes the combined bonus-plus-paycheck amount and can withhold well above 22% on large bonuses. Retirement contributions deducted from the bonus check can also reduce the net further.
If my bonus was over-withheld, when do I get the money back?
When you file your tax return for the year. Withholding is an advance payment toward your annual tax liability — it isn't a separate bonus tax. If the flat 22% (plus FICA) withheld from your bonus exceeds the tax the bonus actually added, the excess increases your refund (or shrinks your balance due) when you file. You don't need to do anything special to claim it; it reconciles automatically on Form 1040. If you'd rather have the money during the year instead of waiting for a refund, you can offset the over-withholding by adjusting your Form W-4 — for example, entering an amount on Step 3 or reducing Step 4c extra withholding — though your employer will still withhold the flat rate on future bonuses.
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