This bonus withholding calculator shows exactly how much tax comes out of a bonus using the IRS percentage (flat) method — a flat 22% federal rate — plus FICA and any state supplemental tax. Enter your bonus and rates below to see your withholding and net bonus. Remember: this is withholding, not your final tax, which is reconciled when you file.
Using the percentage method with no state tax, a $5,000 bonus has 22% federal ($1,100) and 7.65% FICA ($382.50) withheld — total $1,482.50 — leaving you with $3,517.50. Add a 5% state supplemental rate and another $250 comes out, netting $3,267.50. The calculator above lets you plug in your own bonus and state rate.
The IRS treats bonuses as supplemental wages. Under the percentage method, the employer withholds a flat 22% for federal income tax on the bonus (rising to 37% on the portion of supplemental wages above $1 million in a calendar year). This is the simplest and most common approach for a separately issued bonus check. FICA (Social Security + Medicare) and state supplemental tax come out on top of the 22%.
| Withholding piece | Rate | On a $5,000 bonus |
|---|---|---|
| Federal (percentage method) | 22% | $1,100.00 |
| Social Security | 6.2% | $310.00 |
| Medicare | 1.45% | $72.50 |
| Net bonus (no state) | — | $3,517.50 |
Employers can use one of two methods, and the difference can be dramatic:
If far more than 22% disappeared from your bonus, your employer almost certainly used the aggregate method. The good news: it is only withholding. Any over-withholding is refunded when you file, because your bonus is ultimately taxed at your real marginal rate, not the withholding rate.
The 22% flat rate is a withholding shortcut, not a final tax. When you file, your bonus is folded into your total taxable income and taxed at your actual marginal bracket. If you are in the 12% bracket, withholding 22% over-collected, and you get the difference back. If you are in the 32% or 35% bracket, 22% under-withheld and you may owe at filing. To avoid a surprise either way, high earners sometimes ask payroll to withhold extra, while lower earners simply receive a larger refund.
There is a hard rule for very large bonuses: any supplemental wages above $1,000,000 in a calendar year must be withheld at the top rate of 37%, regardless of your W-4. The first $1 million can still use the 22% flat rate; only the excess jumps to 37%. Set the federal rate field to 37% in the calculator to model a bonus or portion that falls under this rule.
Flat 22% federal under the percentage method (37% over $1M/year), plus 7.65% FICA and any state rate. A $5,000 bonus nets $3,517.50 with no state tax.
No, it is only withholding. Your bonus is taxed at your real marginal rate when you file, so you may get part back or owe more.
Percentage method withholds a flat 22% on the bonus separately; the aggregate method lumps it with your regular pay and often withholds more upfront.
Your employer likely used the aggregate method, which applies your normal withholding tables to the combined pay. The excess is refunded at filing.