Bonus Tax Calculator

Enter your bonus, choose the withholding method your employer uses, and pick your filing status and state to estimate how much of the bonus will be withheld and what lands in your account.

Short answer: most employers withhold a flat 22% federal income tax from a bonus paid separately from your regular wages, plus 7.65% for Social Security and Medicare and any state tax. That 22% is only a prepayment. Your real tax on the bonus is whatever extra tax it adds to your annual return at your actual bracket, so you may get some back (if you're in the 10% or 12% bracket) or owe more (if you're in the 24% bracket or above).

This calculator is for informational purposes only, and its results are estimates; your employer's payroll system and your final Form 1040 determine the real numbers.

How does the bonus tax calculator work?

The tool asks for nine things:

Flat mode withholds 22% of the bonus, and 37% on the part of this year's supplemental wages above $1 million. Aggregate mode follows IRS Publication 15: it adds the bonus to one regular paycheck, figures withholding on that combined check with the 2026 Pub 15-T percentage method (Form W-4 from 2020 or later, nothing in Steps 2–4), subtracts the withholding on the regular check alone, and withholds the difference. Above $1 million of supplemental wages the tool switches to the mandatory 37% rule.

What the result shows

• Federal income tax withheld under the method you chose, with both methods side by side
• Social Security (6.2%) on the part of the bonus that fits under the $184,500 wage base, given your year-to-date wages
• Medicare (1.45%) on the whole bonus
• Additional Medicare (0.9%) only on the part of your year-to-date wages from this employer above $200,000
• State withholding at the state's 2026 top rate (California's 10.23% bonus rate), or your override
• Net bonus, the total withheld, and the estimated actual federal tax the bonus adds to your year, based on your regular pay × pay periods and the standard deduction

State withholding is the roughest line. Many states publish their own supplemental rate or have employers use their regular tables; enter your state's published rate in the override field for a closer number. Nine states have no wage income tax: Alaska, Florida, Nevada, New Hampshire, South Dakota, Tennessee, Texas, Washington, and Wyoming.

How do employers withhold federal tax on a bonus?

Bonuses are "supplemental wages" along with commissions, severance, back pay, awards, and accumulated sick-leave payouts. Pub 15, section 7 gives employers these options:

1. Bonus paid together with regular pay and not itemized separately: withhold on the total as if it were one regular paycheck.
2. Bonus identified separately, and you had income tax withheld from regular wages this year or last year: the employer can choose either
   • (a) the flat-rate method: 22% of the bonus, no other percentage allowed, or
   • (b) the aggregate method: add the bonus to the regular wages for the period, figure withholding on the total with the Pub 15-T tables, subtract what was (or will be) withheld from the regular wages, and withhold the difference from the bonus.
3. No income tax withheld from your regular wages this year or last year: the employer must use the aggregate method.
4. Supplemental wages above $1 million in the calendar year: the excess is withheld at 37%, mandatory, regardless of your W-4.

Social Security, Medicare, and FUTA apply to bonuses no matter which income tax method is used.

Worked example: flat 22% vs aggregate on a $10,000 bonus

Profile: single, $85,000 salary paid biweekly ($3,269.23 per check), $60,000 paid so far this year, a 2020-or-later Form W-4 with nothing in Steps 2–4, no pre-tax deductions, bonus paid in a separate check, no state income tax. These are the numbers the calculator shows for those inputs.

Flat-rate method

• Federal income tax: $10,000 × 22% = $2,200.00
• Social Security: $10,000 × 6.2% = $620.00
• Medicare: $10,000 × 1.45% = $145.00
• Net before state tax: $10,000 − $2,200 − $620 − $145 = $7,035.00

Aggregate method (2026 Pub 15-T annual percentage method, single standard table)

1. Combine bonus and regular pay: $3,269.23 + $10,000 = $13,269.23
2. Annualize: $13,269.23 × 26 = $344,999.98
3. Subtract the Worksheet 1A line 1g amount for single filers: $344,999.98 − $8,600 = $336,399.98
4. Table row $263,725–$648,100: $58,448 + 35% × ($336,399.98 − $263,725) = $58,448 + $25,436.24 = $83,884.24
5. Per period: $83,884.24 ÷ 26 = $3,226.32
6. Withholding on the regular check alone: ($85,000 − $8,600) = $76,400 → $5,800 + 22% × ($76,400 − $57,900) = $9,870 → $9,870 ÷ 26 = $379.62
7. Bonus withholding: $3,226.32 − $379.62 = $2,846.70 (28.5% of the bonus)

What you actually owe on it. Using the 2026 brackets in Rev. Proc. 2025-32 and the $16,100 single standard deduction, taxable income is $68,900 without the bonus and $78,900 with it. Both sit inside the 22% bracket ($50,400–$105,700), so the bonus adds exactly $10,000 × 22% = $2,200 of tax.

The aggregate method over-withholds here because step 2 treats a one-time $10,000 as if you earned it every two weeks, which pushes the annualized figure into the 35% row. You get the $646.70 back as part of your refund, but you wait for it.

Is 22% bonus withholding enough?

It depends entirely on your bracket. The table below compares 22% withholding with the extra federal income tax each bonus creates, using 2026 brackets and the standard deduction, assuming the salary is the only income.

How two of those rows work:

• $40,000 salary: taxable income goes from $23,900 to $28,900, all inside the 12% bracket ($12,400–$50,400). Extra tax = $5,000 × 12% = $600.
• $190,000 salary: taxable income goes from $173,900 to $213,900. Tax on $173,900 = $17,966 + 24% × $68,200 = $34,334. Tax on $213,900 = $41,024 + 32% × $12,125 = $44,904. Extra tax = $44,904 − $34,334 = $10,570, of which $12,125 of the bonus is taxed at 32%.

The pattern: if the bonus stays inside the 22% bracket, flat withholding is close to right. In the 10%/12% brackets it over-withholds. Once the bonus pushes you into the 24%, 32%, or higher brackets, 22% falls short, and the gap widens with a second earner's income, investment income, or side income that payroll never sees.

What happens with bonuses over $1 million?

The 37% rule looks at all supplemental wages the employer (and businesses under common control) has paid you during the calendar year, not just the current check.

Example: one $1,500,000 bonus, no earlier supplemental pay

• First $1,000,000 × 22% = $220,000
• Next $500,000 × 37% = $185,000
• Federal withholding: $405,000

Example: $400,000 of commissions earlier in the year, then an $800,000 bonus

• Room left under $1 million: $1,000,000 − $400,000 = $600,000
• $600,000 × 22% = $132,000
• $200,000 × 37% = $74,000
• Federal withholding on the bonus: $206,000

Enter the $400,000 in "Bonuses Already Paid This Year" and the calculator does this split for you, showing $206,000 of federal withholding on the $800,000 bonus.

How are Social Security and Medicare figured on a bonus?

• Social Security: 6.2% until your year-to-date wages reach $184,500 for 2026 (Pub 15). If you're at $175,000 when a $20,000 bonus arrives, only $9,500 is taxed: $9,500 × 6.2% = $589.
• Medicare: 1.45% on every dollar, no cap.
• Additional Medicare: 0.9% withheld on wages above $200,000 from that employer. The tax itself starts at $200,000 for single and head of household filers, $250,000 for married filing jointly, and $125,000 for married filing separately, so a married couple may get some of it back (or owe more) on Form 8959.

Timing matters. A single filer earning $190,000 who gets a $40,000 bonus in March pays full Social Security on the bonus ($2,480) and no Additional Medicare at that point, because year-to-date wages are well under $200,000. Social Security withholding then stops on later paychecks once the $184,500 base is reached, and the 0.9% starts on the paycheck that pushes year-to-date wages past $200,000. Over the full year, Additional Medicare comes to ($230,000 − $200,000) × 0.9% = $270.

How to use the result to avoid a surprise in April

1. Run the method your employer uses (ask payroll; flat 22% is most common for a separate bonus check) and enter your regular pay per check so the tool can estimate your salary.
2. Compare the federal withholding line with "Estimated Actual Federal Tax on the Bonus." If the actual tax is higher, the difference is your likely shortfall; if it's lower, expect that much back. The estimate assumes your salary is your only income and you take the standard deduction.
3. Cover a shortfall by entering an extra per-paycheck amount on Form W-4 Step 4(c) for the rest of the year, or by making an estimated payment (see how to pay quarterly estimated taxes). Withholding counts as paid evenly through the year, so a December W-4 change can still fix an underpayment that started in spring.
4. Bank an expected refund rather than spending it: if you're in the 12% bracket, roughly 10 cents of every bonus dollar withheld at 22% comes back after you file.

The tax withholding calculator checks your whole-year withholding against your projected tax once the bonus is in.

Common bonus withholding mistakes

• Treating 22% as your bonus tax rate. It's a withholding convention. The bonus is taxed at your marginal rate on your return.
• Forgetting FICA when budgeting. On a $10,000 bonus, Social Security and Medicare take $765 before any income tax.
• Assuming the aggregate method means a bigger tax bill. It only means bigger withholding on that check. The extra comes back when you file if your real bracket is lower.
• Missing a second job or spouse's income. Payroll withholds as though the job is your only income. Two earners can land in the 24% bracket together even if each paycheck is withheld at lower rates.
• Not checking the cap on retirement deferrals. If your plan lets you defer part of a bonus into a 401(k), the 2026 employee limit is $24,500 ($32,500 at 50+, $35,750 at ages 60–63), per IRS Notice 2025-67. A deferral lowers income tax withholding on the bonus but not Social Security or Medicare.

Edge cases worth knowing

• Bonus paid in the same check as salary, not itemized: the flat 22% option isn't available; the whole check is withheld as regular wages, which usually looks like aggregate-method withholding.
• Paid in January vs December: the tax year follows the payment date, not the year the bonus was earned. A bonus earned in 2026 but paid January 2027 is 2027 income.
• Signing bonuses and retention bonuses are supplemental wages too. If you must repay one in a later year, the repayment rules are separate and more complicated than a simple refund.
• Overtime pay is also supplemental, though most employers treat it as regular wages. Under the One Big Beautiful Bill Act, the premium portion of qualified overtime can be deducted (up to $12,500, or $25,000 joint); bonuses don't qualify. See the no tax on overtime calculator.

Related tools and guides

For the reasoning behind each withholding method, deferral strategies, and timing ideas, read how bonuses are taxed. To see how a regular paycheck is built line by line, follow the steps in how to calculate your paycheck after taxes or run the paycheck after-tax calculator. To see which bracket your bonus lands in, use the federal tax bracket calculator, and for every 2026 threshold on one page, see the 2026 IRS inflation adjustments guide.