Bonus Tax Calculator: See How Much of Your Bonus You Will Actually Keep
Use our Bonus Tax Calculator to estimate how much tax will be withheld from your year-end, performance, or signing bonus in 2025. Compare flat-rate vs. aggregate method and see how Uncle Kam clients reduce that number with smarter strategy.
How it works
Enter Your Bonus Amount
Provide your expected bonus amount—whether it’s already received or anticipated this year.
Select Flat-Rate or Aggregate Method
Choose how your employer withholds taxes (or let us estimate it for you).
Review Your After-Tax Bonus
See how much you’ll keep and how your bonus will be taxed—before it lands in your account.
Need Professional Tax Help?
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What Is Bonus Tax?
Bonus tax refers to the federal income tax withheld from supplemental wages — which include bonuses, commissions, overtime, and severance pay. The IRS allows employers to use one of two withholding methods: the flat-rate method (22%) or the aggregate method. The method your employer uses determines how much is withheld from your check, but it does not change your actual tax liability — only your year-end reconciliation.
Many employees are surprised to see 22%–37% withheld from their bonus. This calculator helps you estimate that withholding before it happens so you can plan accordingly.
2025 Bonus Tax Withholding Rates
The IRS sets the flat supplemental withholding rate at 22% for bonuses up to $1 million. For bonuses exceeding $1 million in a calendar year, the rate jumps to 37% on the amount over $1 million.
| Bonus Amount | Federal Withholding Rate | Authority |
|---|---|---|
| Up to $1,000,000 | 22% flat rate | IRC §3402(g) |
| Over $1,000,000 | 37% on excess | Top marginal rate |
| Aggregate Method | Varies (10%–37%) | Based on combined bracket |
Flat-Rate vs. Aggregate Method
| Method | How It Works | Best For |
|---|---|---|
| Flat-Rate (22%) | Employer withholds flat 22% from bonus, separate from regular paycheck | Employees in 22%–24% bracket |
| Aggregate Method | Bonus added to most recent regular paycheck; total taxed at combined bracket rate | Employees in lower brackets (10%–12%) |
State Taxes on Bonuses
Most states also withhold state income tax from bonuses. This calculator estimates federal withholding only — add your state's rate for total estimated withholding.
| State | Supplemental Withholding Rate |
|---|---|
| California | 10.23% flat supplemental rate |
| New York | 11.70% (NYC residents add 3.876%) |
| Texas | No state income tax |
| Florida | No state income tax |
| Illinois | 4.95% flat rate |
| Georgia | 5.49% flat rate (2025) |
| New Jersey | Regular income tax rates (1.4%–10.75%) |
| Washington | No state income tax |
Real Bonus Tax Examples
Example 1: $15,000 Bonus — Middle-Income Employee
Situation: W-2 employee, $75,000 salary, $15,000 year-end bonus. Employer uses flat-rate method.
| Item | Amount |
|---|---|
| Gross bonus | $15,000 |
| Federal withholding (22%) | -$3,300 |
| Social Security (6.2%) | -$930 |
| Medicare (1.45%) | -$218 |
| State tax (est. 5%) | -$750 |
| Net bonus received | ~$9,802 |
Example 2: $50,000 Bonus — High-Income Employee
Situation: W-2 employee, $200,000 salary (32% bracket), $50,000 performance bonus. Flat-rate method.
| Item | Amount |
|---|---|
| Gross bonus | $50,000 |
| Federal withholding (22%) | -$11,000 |
| Medicare (1.45% + 0.9% Additional) | -$1,175 |
| State tax (est. 9.3% CA) | -$4,650 |
| Net bonus received | ~$33,175 |
Note: This employee is in the 32% bracket but only 22% was withheld. They will owe ~$5,000 more at tax time.
5 Legal Ways to Reduce Tax on Your Bonus
1. Max Out Pre-Tax Retirement Contributions
Contribute the maximum to your 401(k) — $23,500 in 2025 ($31,000 if 50+). Every dollar contributed reduces taxable income dollar-for-dollar.
2. Contribute to an HSA
If you have a high-deductible health plan, contribute the 2025 HSA maximum: $4,300 (individual) or $8,550 (family). HSA contributions reduce AGI directly.
3. Defer the Bonus to January
If your employer allows it, request your bonus be paid in January. This defers the income to the next tax year — useful if you expect lower income next year.
4. Tax-Loss Harvesting
Realize investment losses before year-end to offset bonus income. Capital losses offset ordinary income up to $3,000 per year, with excess carried forward.
5. Charitable Contributions (Bunching or DAF)
Donate appreciated stock or use a Donor-Advised Fund (DAF) in the same year as your bonus to take the full deduction now while distributing grants over time.
Bonus Tax for Business Owners
| Entity Type | How Bonus Is Taxed | Key Consideration |
|---|---|---|
| S-Corp Owner | W-2 wages — subject to payroll taxes + income tax | Must be reasonable compensation; deductible to the S-Corp |
| C-Corp Owner | W-2 wages — deductible to the corporation | Avoids double taxation vs. dividends |
| Sole Proprietor / LLC | No "bonus" — all profit is self-employment income | Subject to 15.3% SE tax on net earnings |
| Partnership | Guaranteed payments taxed as ordinary income + SE tax | Reported on Schedule K-1 |
More Frequently Asked Questions
Is my bonus taxed at a higher rate than my regular paycheck?
Not necessarily. The 22% flat withholding rate is often higher than what lower-income employees actually owe, and lower than what high-income employees owe. Withholding is an estimate — your actual rate is determined at year-end.
Do I pay Social Security and Medicare tax on my bonus?
Yes. Bonuses are subject to FICA: 6.2% Social Security (up to $176,100 wage base in 2025) and 1.45% Medicare. High earners also pay the 0.9% Additional Medicare Tax on wages over $200,000 (single) or $250,000 (married).
Can I put my entire bonus into my 401(k) to avoid taxes?
You can contribute up to the annual 401(k) limit ($23,500 in 2025; $31,000 if 50+) from your bonus. Contributions reduce taxable income but not FICA taxes.
What if I receive a signing bonus and leave the company?
If you repay a signing bonus in a later year, you may claim a deduction or tax credit under IRC §1341 (Claim of Right doctrine).
How does a bonus affect my tax bracket?
Only the income within each bracket is taxed at that rate. If your bonus pushes you into the next bracket, only the amount above the threshold is taxed at the higher rate.
Are bonuses included in W-2 wages?
Yes. All bonus payments are included in Box 1 (Wages, tips, other compensation) of your W-2, combined with regular wages.
Key Terms
- Supplemental Wages
- Wages paid in addition to regular wages, including bonuses, commissions, overtime, and severance. Subject to special withholding rules under IRC §3402(g).
- Flat-Rate Method
- A withholding method where the employer withholds a flat 22% from supplemental wages, separate from regular paycheck withholding.
- Aggregate Method
- A withholding method where the bonus is combined with the most recent regular paycheck and taxed at the applicable bracket rate for the combined amount.
- FICA Taxes
- Federal Insurance Contributions Act taxes: 6.2% Social Security + 1.45% Medicare. Bonuses are fully subject to FICA.
- Additional Medicare Tax
- An extra 0.9% Medicare tax on wages over $200,000 (single) or $250,000 (married). Applies to bonuses that push total wages over the threshold.
- Marginal Tax Rate
- The tax rate applied to the last dollar of income. In a progressive system, only income within each bracket is taxed at that bracket's rate.
Why Use This Calculator?
Frequently Asked Questions
What’s the flat-rate bonus tax in 2025?
It’s currently 22% federally for bonuses under $1 million. This calculator uses the latest IRS guidance for your estimate.
What is the aggregate method?
It’s when your employer adds your bonus to your regular paycheck and withholds taxes based on your combined total income. This often results in higher withholding than flat-rate.
Can I reduce the taxes on my bonus?
Yes—with proper planning. Contributions to a Solo 401(k), DB plan, or timing strategies can all reduce your taxable income.
What should I do after I get my estimate?
Book a call with our team and we’ll help you plan how to time or structure your bonus for maximum after-tax value.
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