Sign-on bonuses are taxed as ordinary income, but the withholding you see on the paycheck usually doesn’t match your final tax. The IRS classifies them as supplemental wages, so most employers withhold federal income tax at a flat 22%, plus Social Security and Medicare. That 22% is a prepayment, not a special bonus rate. When you file, the bonus is added to the rest of your income and taxed at your regular bracket, which means you may owe more in April or get some of the withholding back.
How Employers Withhold on the Bonus
The IRS defines supplemental wages as payments outside your regular salary or hourly pay for a standard payroll period. Bonuses, commissions, overtime, severance, back pay, and awards all sit in this bucket.1Internal Revenue Service. Publication 15 (2026), (Circular E), Employer’s Tax Guide A sign-on bonus qualifies because it sits on top of your base compensation and doesn’t recur on a schedule. Whether it’s paid on day one or after a 90-day probation, the tax treatment is the same.
Employers pick one of two withholding methods, and the choice affects your net check.
Flat 22% (Percentage Method)
If your total supplemental wages for the year are $1 million or less, the employer can withhold a flat 22% for federal income tax on the bonus. No other flat rate is allowed.1Internal Revenue Service. Publication 15 (2026), (Circular E), Employer’s Tax Guide This is the most common approach for sign-on bonuses because it’s simple: 22% is applied to the bonus alone, without reference to your regular paycheck or W-4 elections.
Aggregate Method
Under the aggregate method, the employer adds the bonus to your regular wages for that pay period and withholds as if the combined amount were a single paycheck, using the standard graduated tables in Publication 15-T. Tax already withheld from your regular wages is subtracted, and the remainder comes out of the bonus.1Internal Revenue Service. Publication 15 (2026), (Circular E), Employer’s Tax Guide Because the inflated paycheck lands in a higher withholding bracket for that one period, this method often takes more out than the flat 22% would. The extra usually comes back as a refund when you file.
Bonuses Above $1 Million
Once your total supplemental wages for the year exceed $1 million, the rate on the portion above that threshold jumps to a mandatory 37%, regardless of what your W-4 says.1Internal Revenue Service. Publication 15 (2026), (Circular E), Employer’s Tax Guide
Why 22% Is Not Your Real Tax Rate
This is the part that trips people up. The 22% flat rate is withholding, not taxation. There’s no separate “bonus tax” schedule. Your employer reports the bonus alongside regular salary in Box 1 of your W-2, and the IRS taxes your total income at the applicable graduated rates.
What that means in practice:
- If your marginal bracket is 32%, 22% withholding wasn’t enough, and you’ll owe the difference at filing.
- If your marginal bracket is 12%, too much was withheld, and you’ll get some back.
- If you’re right around 22%, you’ll come out close to even on the bonus itself.
Anyone who tells you bonuses are “taxed at 22%” is confusing withholding with the actual tax bill. The distinction matters most for higher earners, who can face an unpleasant balance due if they treat the withholding as the final word.
Social Security and Medicare
Sign-on bonuses are wages for FICA purposes, so both you and your employer owe payroll taxes on the payment.2Office of the Law Revision Counsel. 26 USC 3121 – Definitions
- Social Security: 6.2% from your paycheck on wages up to $184,500 in 2026. If your base salary already exceeds that ceiling before the bonus hits, the bonus escapes Social Security tax.3Social Security Administration. Contribution and Benefit Base
- Medicare: 1.45% from your paycheck with no income ceiling.
- Additional Medicare Tax: 0.9% on wages above $200,000 for most filers ($250,000 married filing jointly, $125,000 married filing separately). Your employer starts withholding this once your year-to-date wages cross $200,000, regardless of filing status; any adjustment based on your actual status happens on your return.4Internal Revenue Service. Topic No. 560, Additional Medicare Tax
A large sign-on bonus can push you past the Social Security wage base or into Additional Medicare territory earlier in the year than you would otherwise reach. If your base salary is near $184,500, running the numbers before negotiating the timing of the bonus is worth the effort.
State Income Tax
Most states with an income tax also withhold on supplemental wages. Some set a flat state bonus rate, others follow the federal graduated approach. A few states have no income tax at all. Your payroll department or the state’s withholding tables will tell you what applies.
How the Bonus Shows Up on Your W-2
The gross amount of the bonus is folded into Box 1 of your W-2 along with your regular salary. W-2 instructions specifically list signing bonuses as an item that must be included in wages. Social Security wages appear in Box 3 and Medicare wages in Box 5, both including the bonus. Federal income tax withheld lands in Box 2, Social Security tax in Box 4, and Medicare tax in Box 6.5Internal Revenue Service. 2026 General Instructions for Forms W-2 and W-3
The bonus is not broken out on its own line. If you want to track exactly how much was withheld from it, save the pay stub from the period when it was paid.
If You’re Paid as a Contractor Instead
The rules above assume you’re a W-2 employee. If the sign-on payment goes to you as an independent contractor, the company reports it on Form 1099-NEC when the total for the year is $600 or more, and no tax is withheld at the source.6Internal Revenue Service. Instructions for Forms 1099-MISC and 1099-NEC You pay income tax plus the full 15.3% self-employment tax yourself, typically through quarterly estimated payments. The upfront tax cost is roughly double what it would be on an equivalent W-2 bonus.
Ways to Cut the Tax Hit
You can’t make the tax disappear, but you can shape it.
If your 401(k) plan allows deferrals from bonus payments, you can route some or all of the bonus into your retirement account and reduce your taxable income for the year. The 2026 elective deferral limit is $24,500, or $31,000 if you’re 50 or older.7Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026; IRA Limit Increases to $7,500 Not every plan includes bonuses in eligible compensation, so check the plan document or ask HR before you count on it.
Timing matters if your income varies. If this year is unusually high and next year will be lower, negotiating the bonus into the lower-income year can shave your marginal rate. If you’re already at the top of the bracket and will stay there, the timing question is mostly about making sure your total withholding covers your liability so you don’t hit an underpayment penalty.
What Happens If You Have to Pay the Bonus Back
Many contracts include a clawback: leave before a certain date and you owe the bonus back. The tax consequences depend heavily on when you repay.
Same-Year Repayment
Return the bonus in the same calendar year you received it and the mechanics are clean. You repay only the net amount you actually received after withholding, and payroll reverses the income and recovers the taxes that were withheld. Your W-2 for the year reflects the corrected, lower wages, as if the bonus never happened.
Repayment in a Later Year
Repay in a later year and it gets expensive. You typically owe back the gross amount of the bonus, not the net you took home. You’re writing a check for money you already sent to the IRS, and you have to recover those taxes through your own return.
If the repayment is more than $3,000, the claim of right doctrine gives you two options. You can take an itemized deduction for the repayment on your current-year return, or you can compute a tax credit equal to the amount your prior-year tax would have dropped if the bonus had never been paid to you. You use whichever produces the lower bill.8Office of the Law Revision Counsel. 26 USC 1341 – Computation of Tax Where Taxpayer Restores Substantial Amount Held Under Claim of Right Publication 525 walks through both methods, including how to refigure the prior-year tax without the bonus income.9Internal Revenue Service. Publication 525 (2025), Taxable and Nontaxable Income
If the repayment is $3,000 or less, the 2017 tax law changes wiped out the miscellaneous itemized deduction that used to cover these small wage repayments. Under current rules, a later-year repayment of $3,000 or less may not be deductible at all.9Internal Revenue Service. Publication 525 (2025), Taxable and Nontaxable Income Worth knowing before you sign a clawback for a modest amount.