Bonus and Supplemental Wage Tax in 2026: IRS 22% and 37% Rules
Updated May 2026 · 15 min read
Bonuses are not taxed by a special "bonus tax" at filing time. They are wages. The confusion comes from withholding. Payroll may withhold federal income tax from a bonus at a flat 22%, while your final tax return treats the bonus as part of total wages alongside salary, commissions, equity income, and everything else. If your marginal rate is higher than 22%, the bonus can be underwithheld. If your marginal rate is lower, it can be overwithheld. The paycheck is not the final answer.
Withholding Is Not the Final Tax
Employees often ask why a $10,000 bonus did not produce a $10,000 increase in take-home pay. The answer is usually a stack of withholding items: federal income tax withholding, employee Social Security tax until the annual wage base is reached, Medicare tax with no wage base, Additional Medicare Tax withholding after wages exceed $200,000, state withholding, local withholding, retirement deferrals, and benefit deductions. Some of those are final taxes; others are prepayments. Federal income tax withholding is a prepayment against the Form 1040 bill.
The IRS supplemental wage rules only tell the employer how much federal income tax to withhold from that wage payment. They do not create a separate tax bracket for bonuses. At filing time, a $12,000 bonus and $12,000 of regular salary both land in wages on Form W-2. The final federal income tax depends on annual taxable income, deductions, credits, filing status, and other income. That is why a bonus withheld at 22% can still produce a tax bill for a high-income employee in the 32%, 35%, or 37% bracket.
What Counts as Supplemental Wages
Publication 15 defines supplemental wages as wage payments that are not regular wages. The IRS list includes bonuses, commissions, overtime pay if the employer treats it as supplemental, accumulated sick leave, severance pay, awards, prizes, back pay, retroactive pay increases, taxable fringe benefits, nonaccountable expense allowances, and reported tips. The exact label on the pay stub is less important than whether the payment is separate from normal wages and handled under the supplemental wage rules.
Employers also have to keep the payroll-tax categories straight. Publication 15 says that regardless of the federal income tax withholding method used for supplemental wages, those wages are subject to Social Security, Medicare, and FUTA taxes unless a specific exception applies. A bonus can be withheld at 22% for federal income tax and still have 6.2% employee Social Security withheld if the employee has not reached the 2026 Social Security wage base of $184,500 under Publication 15. Medicare applies at 1.45% with no wage base, and the 0.9% Additional Medicare Tax withholding begins when an employer pays wages above $200,000 in the calendar year.
| Rule | 2026 treatment | Primary IRS source |
|---|---|---|
| Optional flat federal withholding | 22% on eligible supplemental wages up to $1 million | Pub. 15, section 7 |
| Mandatory high-income supplemental rate | 37% on supplemental wages over $1 million | Pub. 15, section 7 |
| Aggregate method | Add bonus to regular wages, compute withholding on total, subtract regular withholding | Pub. 15, section 7 |
| Social Security | 6.2% employee and 6.2% employer up to $184,500 of 2026 wages | Pub. 15 |
| Medicare | 1.45% employee and 1.45% employer on all covered wages | Pub. 15 |
The Percentage Method: The Familiar 22%
The percentage method is the rule most employees recognize. If the employer pays supplemental wages separately, or states the bonus amount separately in a combined payment, and income tax was withheld from the employee's regular wages in the current or immediately preceding calendar year, Publication 15 allows the employer to withhold a flat 22% from supplemental wages of $1 million or less. The IRS wording is strict: no other percentage is allowed for that optional flat method.
That strictness cuts both directions. An employee cannot force payroll to use 24% under the flat supplemental method just because that would match a projection. The employee can submit a Form W-4 with extra withholding on Step 4(c), but the optional flat rate itself is fixed by Publication 15. Likewise, a payroll department should not use 10% or 12% on an eligible separately paid bonus merely because the employee asked for it. If the employer chooses the flat method, 22% is the number.
Worked Example: Amanda's $12,000 Bonus
Amanda earns an $80,000 salary and receives a separate $12,000 performance bonus in June 2026. Her year-to-date wages are below the 2026 Social Security wage base. Her employer uses the Publication 15 percentage method for federal income tax withholding.
| Withholding item | Calculation | Amount |
|---|---|---|
| Federal income tax withholding | $12,000 × 22% | $2,640.00 |
| Employee Social Security | $12,000 × 6.2% | $744.00 |
| Employee Medicare | $12,000 × 1.45% | $174.00 |
| Total federal withholding before state/local items | $3,558.00 | |
| Bonus check before state/local/benefits | $12,000 - $3,558 | $8,442.00 |
The employer also pays its own matching Social Security and Medicare on the bonus: $744.00 plus $174.00, or $918.00, assuming Amanda remains under the Social Security wage base. That employer match does not come out of Amanda's check, but it matters to a business budgeting bonus cost. Use our bonus tax calculator for the employee check and our employer cost calculator when the company needs the gross labor cost.
The Aggregate Method
The aggregate method feels less intuitive because it treats the bonus as if it were part of a regular payroll run. Publication 15 says that if supplemental wages are paid with regular wages and the employer does not specify each amount, federal income tax is withheld as if the total were one regular wage payment for that payroll period. If the supplemental wages are separately identified, the employer may still use an aggregate calculation: add the supplemental wages to regular wages, compute withholding on the combined amount, subtract withholding already taken from regular wages, and withhold the remainder from the supplemental wages.
The IRS gives a clean section 7 example using a $2,000 salary payment and a $1,000 bonus. In the aggregate version, the employer computes withholding on $3,000, subtracts the amount already withheld from the $2,000 regular wage payment, and withholds the difference from the bonus. In that example, the bonus withholding is $114. In the flat percentage version with the same $1,000 bonus, the withholding is $220. Same bonus, same employee, different permitted method. That is why two coworkers at different employers can receive similar bonuses and see very different federal withholding.
The 37% Rule Above $1 Million
Publication 15 has a separate rule once supplemental wages paid to an employee during the calendar year exceed $1 million. The excess is subject to withholding at 37%, the highest rate listed in the 2026 supplemental wage rule, without regard to the employee's Form W-4. In determining whether the employee crossed $1 million, employers include supplemental wages paid by businesses under common control.
Marcus is a sales executive who receives a single $1,250,000 commission in 2026, paid separately from regular wages. Assume his employer may use the flat method for the first $1 million. Federal income tax withholding is $220,000 on the first $1,000,000 at 22% and $92,500 on the $250,000 excess at 37%, for total federal income tax withholding of $312,500. Payroll still has to apply Social Security and Medicare rules separately. If Marcus had already reached the Social Security wage base before the commission, no additional Social Security would be withheld, but Medicare and Additional Medicare Tax withholding would still matter.
How Bonuses Interact With Form W-4
Form W-4 controls regular wage withholding and can add extra withholding per pay period, but it does not let an employee rewrite the 22% optional supplemental rate. If a bonus is likely to be underwithheld, one practical move is to increase Step 4(c) for the remaining paychecks. Suppose Amanda's projection after the June bonus shows she will be $1,800 short by December and she has 12 regular paychecks left. She can file a revised W-4 with $150 on Step 4(c). That extra withholding from regular wages can cover the bonus gap by year-end.
Employees should remember to reset the W-4 after the goal is met. A $150 extra line left in place for 26 paychecks next year would withhold $3,900, not $1,800. Our W-4 withholding guide covers that pay-period math in more detail.
Employer Checklist for Supplemental Wages
- Identify the payment type. Bonus, commission, severance, taxable fringe, back pay, and similar payments may be supplemental wages under Pub. 15.
- Decide whether the amount is separately identified. That determines whether flat percentage withholding is available or whether the payment is treated as regular wages.
- Confirm regular withholding history. The 22% flat method depends partly on whether income tax was withheld from regular wages in the current or prior year.
- Track the $1 million threshold. The 37% rate applies to the excess supplemental wages over $1 million.
- Do not skip FICA and FUTA. Pub. 15 says supplemental wages remain subject to Social Security, Medicare, and FUTA unless a specific exception applies.
Employee Checklist Before Spending the Bonus
First, read the pay stub by category. Do not just compare gross bonus to net deposit. Second, estimate the full-year tax rate. If 22% federal withholding is below your expected marginal rate, reserve some cash. Third, check whether the bonus pushed you over the Additional Medicare Tax withholding threshold or the Social Security wage base. Fourth, coordinate state taxes; high-tax states can make the net check meaningfully lower than federal-only examples suggest. Finally, if you have equity compensation or a side business in the same year, do a whole-return projection. The bonus may not be the only source of underwithholding.