Why This Can Happen
There are several reasons a bonus might arrive without proper withholding: payroll system error, incorrect classification of the payment, a manual check issued outside the normal payroll run, or an employer who is not familiar with supplemental wage withholding requirements. In all cases, the legal obligation to pay the underlying tax rests with you — regardless of employer error.
Federal and state income tax, Social Security, and Medicare are owed on all wages including bonuses — whether or not your employer withheld them. If the employer failed to withhold, you owe those amounts when you file. Set aside approximately 30-40% of the unwithheld bonus immediately.
What You Owe on an Unwithheld Bonus
Estimated taxes owed on a $10,000 bonus with no withholding
| Tax Component | Rate | On a $10,000 Unwithheld Bonus |
|---|---|---|
| Federal Income Tax | Based on marginal rate (12-24% typical) | $1,200 to $2,400 |
| Social Security | 6.2% (up to wage base) | $620 |
| Medicare | 1.45% | $145 |
| Additional Medicare (if applicable) | 0.9% above $200K | $0 to $90 |
| State Income Tax | Varies by state | $0 to $1,100 |
| Total (typical estimate) | ~30-37% | $3,000 to $3,700 |
How to Pay the Tax Without Penalties
- Calculate your estimated tax owed: 22-35% of the bonus amount depending on your bracket and state
- Set aside that amount immediately in a separate account
- Make an estimated tax payment at IRS.gov (Direct Pay) by the next quarterly deadline
- Quarterly estimated payment deadlines: April 15, June 15, September 15, January 15
- Also make a state estimated payment at your state revenue department website
- When you file your annual return, the estimated payment offsets your total tax due
- If the bonus was large, verify whether adjusted safe harbor payments prevent any underpayment penalty
What to Tell Your Employer
Contact your employer or HR/payroll department immediately. They need to issue a corrected W-2 (W-2c) showing the correct taxable wages even if they did not withhold. The employer may also owe penalties for failure to withhold — that is their liability, not yours. Ensure your W-2 reflects the full bonus amount in Box 1 so your tax return is accurate.
Calculate the Tax You Owe on Your Unwithheld Bonus
Enter the bonus amount, state, and salary to see exactly what federal, state, and FICA you need to pay.