Sign-On Bonus Tax Calculator
A sign-on bonus is taxed exactly like any other bonus: 22% federal supplemental withholding, 7.65% FICA, and your state's rate. Two planning wrinkles are unique: clawback terms (if you leave early, you usually repay the gross amount, which can mean reclaiming withheld tax at filing) and timing (a January start can push the bonus into a single year and briefly over $1M supplemental wages for very large offers).
Quick answer: A $15,000 sign-on bonus nets roughly $8,950–$10,550 after withholding, depending on state. If you repay it under a clawback, you repay the gross $15,000 and recover the excess withholding on your tax return.
| Gross bonus | $15,000.00 |
| Federal supplemental withholding (22%)prepayment — your real tax is set at filing | − $3,300.00 |
| FICA (6.2% SS + 1.45% Medicare) | − $1,147.50 |
| State supplemental (custom 5%) | − $750.00 |
| Net bonus | $9,802.50 |
Withholding-level estimate. The 22% federal rate is a prepayment, not your final tax — excess withholding is refunded when you file. FICA of 7.65% assumes you are under the Social Security wage base for the year. Not tax advice.
| Withholding | Same as any bonus: 22% federal + 7.65% FICA + state |
|---|---|
| Clawback | Repayment is usually the gross amount; recover withheld tax via your return (or a reduced W-2 under a 2026 repayment claim) |
| Timing | Taxed in the year received, not the year you accept |
Common uses
- Compare two offers with different signing bonus sizes
- Understand what lands on day one versus what the clawback clause risks
- Budget a relocation around the net signing bonus