Bonus Tax 2026 Effective Rate Calculator
See exactly how much of your bonus goes to taxes in 2026: federal flat rate (22%), state withholding, and FICA. Compare supplemental vs aggregate withholding methods per IRS Publication 15-T.
How Bonus Taxes Work in 2026
Bonuses are classified as "supplemental wages" by the IRS and are subject to mandatory federal income tax withholding. Under IRS Publication 15-T (2026), the supplemental flat rate is 22% for supplemental wages up to $1 million in a calendar year, and 37% for amounts above $1 million. This flat rate applies regardless of your regular salary or tax bracket — it is a withholding mechanism, not your final tax liability.
The bonus withholding is simply a prepayment toward your annual tax bill. When you file Form 1040, your bonus income is added to all other income, and your actual tax is calculated on the combined total. If 22% was withheld but your true effective rate is lower, you receive the difference as a refund. If your effective rate is higher (e.g., you are in the 32% bracket), you may owe additional tax at filing time. Source: irs.gov/publications/p15. Last updated: May 2026.
Supplemental vs Aggregate Withholding Method
| Method | How Calculated | Who Uses It | Best When |
|---|---|---|---|
| Supplemental (Flat 22%) | 22% of bonus, flat | Most employers by default | Marginal rate ≈ 22% |
| Aggregate | Bonus + regular pay → bracket rate − regular withholding | Employers who choose; required when prior pay not identified | Marginal rate < 22% (lower earners) |
Employers can choose either method unless the bonus is included in a regular paycheck without separate identification, in which case the aggregate method is required. For employees in the 12% bracket, the aggregate method results in less withholding than the 22% flat rate — meaning a bigger net check. For employees in the 24%+ bracket, the 22% flat rate actually withholds less than their true marginal rate, meaning they may owe tax at filing.
FICA and Additional Medicare Tax on Bonuses
Bonuses are subject to FICA taxes: Social Security at 6.2% up to the 2026 wage base of $176,100, and Medicare at 1.45% on all wages. If your combined wages (salary + bonus) exceed $200,000 (single) or $250,000 (MFJ), the Additional Medicare Tax of 0.9% applies to the excess. Your employer withholds the 0.9% surtax only on wages they pay above $200,000 — if you have multiple jobs, you may need to reconcile on Form 8959. Source: IRS Publication 15, irs.gov/taxtopics/tc756.