Bonus Tax Calculator

The 22% is withholding, not tax

When a bonus is paid as a separate check, most employers use the IRS "percentage method": a flat 22% federal withholding (37% on any supplemental wages over $1M for the year). But your actual tax on the bonus is your marginal bracket. If you're in the 12% bracket, 22% over-withholds and the difference comes back in your refund. In the 32–37% brackets, 22% under-withholds and you'll owe the gap in April — worth knowing before you spend it.

FICA doesn't care that it's a bonus

Social Security (6.2%) and Medicare (1.45%) apply to a bonus like any other paycheck. Two wrinkles: Social Security stops once your year's wages pass the cap ($184,500 in 2026) — a late-year bonus after the cap skips it entirely — and an extra 0.9% Medicare kicks in on wages over $200k. Pre-tax 401(k) deferrals reduce income-tax withholding but never FICA.

The aggregate-method surprise

If your bonus is lumped into a regular paycheck instead of cut separately, the employer withholds as if you earned that much every period — which can grab far more than 22% up front. You get it back at filing, but it's the usual reason a bonus check looks shockingly small. Ask payroll which method they use.

The formula

The 37% rate only applies to the slice of your year's total supplemental wages above $1,000,000 (IRC §3402(q); unchanged for 2026 — OBBBA made the TCJA structure permanent). FICA and state withholding stack on top:

• Social Security = 6.2% × the part of the bonus that falls under the $184,500 wage cap, given wages already paid this year
• Medicare = 1.45% × the full bonus, plus 0.9% on the part that pushes year-to-date wages over $200,000
• State = (Bonus − 401(k) deferral) × your state's supplemental withholding rate

Worked example

A $10,000 bonus, $100,000 salary with $50,000 of it already paid, single filer, no state tax, no 401(k) deferral:

• Federal withheld: $10,000 × 22% = $2,200
• Social Security: $10,000 × 6.2% = $620 (nowhere near the $184,500 cap)
• Medicare: $10,000 × 1.45% = $145 (no additional 0.9% — YTD wages stay under $200k)
• Net bonus: $10,000 − $2,200 − $620 − $145 = $7,035, or 70.4% of the bonus

At exactly $100k salary this filer's real marginal federal tax on that $10,000 slice also happens to land at 22% — so the withholding gap is $0, a coincidence of this particular income rather than a rule. Drop the salary to $40,000 (12% bracket) and the real tax on the bonus is only $1,200, so the flat 22% over-withholds by $1,000 — that comes back as part of the refund. Raise it to $500,000 (35% bracket on that slice) and the real tax is $3,500, so 22% under-withholds by $1,300 — owed at filing.