Marginal Tax Rate on Bonus Calculator

Find out exactly how much tax is taken out of your bonus — federal, state, Social Security & Medicare.

Aggregate method: Your bonus is added to your regular salary and taxed at your effective marginal rate — the most accurate approach.
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Where Your Bonus Goes

Federal Tax Bracket Breakdown

How to Use This Bonus Tax Calculator

Enter your annual base salary, your bonus amount, your filing status, and your state. Optionally adjust your 401(k) contribution rate and any other pre-tax deductions — these reduce your taxable income and can meaningfully lower what you owe. Hit Calculate Bonus Tax to instantly see your federal marginal rate, estimated withholding, and net take-home amount.

You can switch between two withholding methods: the Aggregate Method (adds your bonus to your annual salary to find the marginal tax rate — the most accurate) and the Flat Rate Method (the IRS allows employers to withhold a flat 22% on supplemental wages under $1 million).

Why This Matters

Bonuses feel like found money — until you see the check. Someone earning $85,000 who receives a $15,000 bonus might expect to take home $12,000 or more. Instead, they're shocked to find only $9,200 after withholding. That $2,800 gap isn't random — it's the result of landing squarely in the 22% federal bracket, plus state taxes, Social Security (6.2%), and Medicare (1.45%).

Understanding your effective bonus tax rate matters for several practical reasons:

How It's Calculated

Aggregate Method (recommended): Your bonus is added to your annualized salary, federal income tax is calculated on the combined total, then the tax on just your salary is subtracted. The difference is the federal tax attributable to your bonus.

Bonus Federal Tax = Tax(Salary + Bonus) − Tax(Salary)

Flat Rate Method: The IRS permits employers to withhold a flat 22% on supplemental wages up to $1,000,000. It's simpler but often under- or over-withholds compared to your actual marginal rate.

FICA taxes (Social Security + Medicare) apply until you hit the Social Security wage base ($168,600 for 2024). This calculator accounts for YTD earnings you've already paid Social Security on, stopping withholding at the cap.

State tax is applied using a flat marginal rate approximation, which is accurate for flat-tax states and a close estimate for graduated states.

Tips & Common Mistakes

Frequently Asked Questions

Why is so much tax taken out of my bonus?

Bonuses are classified as "supplemental wages" by the IRS, which means employers can withhold at a flat 22% or add them to your regular pay and withhold at your marginal rate. Because bonuses often push your income into a higher bracket temporarily, the withholding can look steep. The actual tax you owe is calculated at year-end on your total income — you may get a refund if too much was withheld.

Is my entire bonus taxed at the higher rate?

No — only the portion of your bonus that falls into a higher bracket is taxed at that higher rate. The US uses a progressive tax system, so the first dollars of your bonus are taxed at your existing rate. Only the amount that crosses a bracket threshold gets the higher rate applied to it.

Can I reduce taxes on my bonus?

Yes. The most effective legal strategy is increasing your 401(k) or HSA contributions, since these reduce your taxable income before the bonus hits. You can also ask your employer to delay paying the bonus until January if that fits your income planning. Some people time charitable donations to offset a bonus year's income.

What's the difference between the aggregate and flat rate methods?

The flat rate method withholds a simple 22% regardless of your actual bracket — it's fast but often inaccurate. The aggregate method adds your bonus to your regular pay and calculates tax on the combined amount, which more closely reflects what you'll actually owe. Your employer chooses the method; you can't control it, but knowing which one they use helps you plan.

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