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Estimate withholding and net pay on a bonus, using the flat federal supplemental wage rate.
$3517.50
Bonuses paid separately from a regular paycheck are commonly withheld using the federal "supplemental wage" method -- a flat percentage rate (22% for amounts up to $1 million, as of recent IRS guidance) applied directly to the bonus, rather than the progressive bracket withholding used on regular paychecks. This is a genuinely different withholding mechanism, which is why a $5,000 bonus's withholding can look quite different from what the same $5,000 added to a regular paycheck would withhold.
Enter your bonus amount, the federal supplemental withholding rate (22% is standard for most bonuses), your state's flat withholding rate if applicable, and the FICA rate (7.65% combined Social Security + Medicare is standard for most employees).
Federal Withholding = Bonus × Supplemental Rate
FICA Withholding = Bonus × FICA Rate
State Withholding = Bonus × State Flat Rate
Net Bonus = Bonus − Federal − FICA − State Withholding
The amount withheld from your bonus isn't necessarily your final tax owed on it -- bonus income is ultimately taxed at your regular marginal rate when you file, so you may get some of the withholding back as a refund (or owe more) depending on how the flat supplemental rate compares to your actual marginal bracket.
Take a hypothetical $10,000 bonus with no state income tax, a 22% federal supplemental rate, and 7.65% FICA. Federal withholding is $2,200, FICA is $765, and the net bonus is $7,035. Now imagine the employee's actual marginal federal bracket is 12%. The federal tax truly owed on that bonus is about $1,200, so roughly $1,000 of the withholding would come back as part of the refund when the year-end return is filed. If the employee's marginal bracket were higher than the flat rate, the opposite could happen and a balance could be due. Withholding is a prepayment, not a final answer.
If you know a bonus is coming, you can compare the flat-rate withholding with what the combined method would withhold, ask payroll which method they use, or adjust your W-4 for the rest of the year so total withholding lines up with what you will actually owe. Pair this tool with the Tax Refund Estimator to see whether your yearly withholding is on track. For questions about your specific situation, a tax professional can give personalized advice.
The IRS allows employers to use a flat "supplemental wage" withholding rate for bonuses instead of the progressive bracket method used on regular pay -- it's a withholding convenience, not necessarily your true final tax rate on that income.
Possibly -- if your marginal tax bracket is lower than the flat supplemental rate, you may see some of that withholding refunded when you file your tax return, since your bonus is ultimately taxed at your real marginal rate, not the flat withholding rate.
No -- some employers instead combine the bonus with a regular paycheck and withhold using the standard progressive method; either approach is IRS-compliant, but they can produce different withholding amounts for the same bonus.
Several withholdings stack on the same payment: federal supplemental tax, Social Security and Medicare, and often state and local tax. Together they can take a large slice of the gross, even though the final yearly tax may differ.
Flat supplemental withholding is set by the employer's payroll method, so it usually cannot be changed for a single payment. You can adjust your W-4 for regular paychecks, which affects overall yearly withholding.
Not separately. You can add a local rate into the state field as a combined percentage if you know it, but confirm the amount with your payroll provider.
Reference: Internal Revenue Service