How to use this calculator
- Choose a cash bonus or shares vesting. For a bonus, enter the amount before tax. For RSUs, enter the shares and the price per share on the vesting day, from your vesting confirmation.
- Choose how your employer withholds. A bonus paid on its own check or line is usually the flat 22%; if your pay stub shows it added to a regular paycheck, choose that. If you already have the stub, you can enter the federal income tax withheld instead.
- Choose the tax year and your filing status, and enter your yearly salary (and your spouse's wages on a joint return).
- Under More options, add your pay so far this year (for the Social Security wage base), earlier bonuses (for the $1,000,000 mark), retirement contributions, other income, children and your Form W-4.
The numbers already filled in are an example. Replace them with your own.
How it's calculated
The rules come from IRS Publication 15, Publication 15-T and the regulation on supplemental wage withholding. The calculator works out the withholding on the bonus check, then your federal return twice, with and without the bonus. Withholding is a prepayment; the return decides the tax.
The bonus check
Say you file single for 2026, earn a $150,000 salary and get a $20,000 bonus on its own check. Your employer withholds a flat 22% for federal income tax, $4,400, without looking at your W-4. Social Security (6.2%, until your pay for the year reaches the wage base) and Medicare (1.45%) take $1,530. You take home $14,070. Once your bonuses for the year from one employer pass $1,000,000, the part above it is withheld at 37%, and above $200,000 of pay from one employer an extra 0.9% of Medicare tax is withheld.
What it adds to your tax
On your return the bonus is taxed at the rates above your salary. Your taxable income rises from $133,900 to $153,900, and your tax by $4,800, about 24.0% of the bonus. With $4,400 withheld, you'd owe about $400 more when you file. With a $300,000 salary and a $50,000 bonus, the bonus is taxed at about 35.9% and the shortfall is $6,500. With a $40,000 salary and a $5,000 bonus it's taxed at 12.0%, so $500 comes back. The calculator also counts what a bonus does to the child tax credit, the Additional Medicare Tax and the net investment income tax.
Added to a paycheck
Some employers add the bonus to a regular paycheck and run the withholding tables on the total, then subtract what they'd withhold from the paycheck alone. The tables treat each paycheck as a year of pay at that level, so a large bonus looks like a very high salary. In the first example, paid every two weeks, that withholds $6,660 from the bonus instead of $4,400, and $1,860 comes back when you file.
Social Security on the check and over the year
Social Security tax stops for the year once your pay from one employer reaches the wage base. If your salary plus the bonus passes it, the bonus check may still pay the full 6.2% if it comes early in the year, but your later paychecks then stop the tax sooner. The calculator shows both: what comes off the check, and what the bonus adds over the year.
RSUs
When 100 shares vest at $200.00, the $20,000 is taxed as pay, the same as the cash bonus above. Your employer covers the withholding by keeping back or selling about 29.65 shares (a sell-to-cover), and you keep about 70.35. Your cost basis in them is $200.00 a share, the value already taxed as pay.
Assumptions and limits
- The amount you'll owe or get back is the bonus's own: it assumes the rest of your pay is withheld correctly for the rest of your return. Your whole return can still owe or refund for other reasons.
- Each of you has one employer. Two employers each withhold Social Security up to the wage base; the excess comes back on your return, which this doesn't figure.
- Federal only: state and local income tax on the bonus aren't included.
- “Added to a paycheck” uses the percentage method in Publication 15-T for a Form W-4 from 2020 or later. The wage bracket tables and payroll systems that round to the dollar can differ by a dollar or two. A W-4 from 2019 or earlier uses allowances, which this doesn't take, and can differ by more. For 2025 it uses the 2025 withholding tables, which were published before that year's tax law changes.
- The flat 22% is allowed only if income tax was withheld from your regular pay this year or last. This checks your regular paycheck this year; if it shows nothing withheld, it uses the paycheck method instead.
- The return uses the standard deduction or your itemized total, whichever is larger, the child tax credit and the credit for other dependents, the senior deduction from the age boxes, the Additional Medicare Tax and the net investment income tax. It doesn't include other credits, the alternative minimum tax, or the overtime, tips and car loan interest deductions.
- All the interest, ordinary dividends and other income you enter is treated as investment income for the net investment income tax; if some of it isn't, the tax shown may be a little high.
- Earlier bonuses are taken as already-taxable amounts, paid in earlier paychecks. An employer that pays two bonuses in the same paycheck adds them together, which can change the withholding by a few dollars. It doesn't cover retirement contributions taken from RSUs, stock options, employee stock purchase plans, 83(b) elections or deferred compensation.
- Adjustments and itemized deductions are used as entered. Deductions that shrink as income rises (the state and local tax deduction above its income limit, the 2026 limit on itemized deductions in the top bracket, student loan interest) aren't followed, so the bonus may add a little more tax than shown.
Input field details
What to enter in each box, where to find the number, and how this calculator treats it. When two calculators give different answers from the same numbers, it's usually because they handle one of these differently.
What you’re getting
A cash bonus, or shares vesting from restricted stock units (RSUs).
How this tool treats itBoth are supplemental wages: taxed as pay in the year you receive them, with the same withholding rules. For RSUs, the shares’ value on the day they vest is the pay.
Bonus amount
The bonus before any tax or deduction comes out.
Where to find itYour bonus letter, or the gross amount on the pay stub that carries it.
How this tool treats itThe IRS calls a bonus a supplemental wage, along with commissions, awards, prizes, back pay, severance and retroactive raises paid separately from your regular pay. All of them are withheld the same way, so you can enter any of them here.
Allowed range$0 to $10,000,000
How your employer withholds
Flat 22% unless your pay stub shows your bonus added to a regular paycheck, or you already know the amount withheld.
Where to find itThe pay stub or vesting statement for the bonus: a separate line or check usually means the flat rate.
How this tool treats itFor a bonus paid separately, the employer may withhold a flat 22% of it, ignoring your W-4, as long as it withheld income tax from your regular pay this year or last. Or it may add the bonus to a regular paycheck, figure the withholding on the total as if you earned that much every pay period, and subtract what it withholds from the paycheck alone (the aggregate method). That usually withholds more, because one large paycheck reads as a year of high pay. Either way the 37% rate applies to bonuses over $1,000,000 for the year. Withholding is a prepayment: your return decides the actual tax.
Federal income tax withheld from it
The federal income tax taken from the bonus, if you already know it.
Where to find itThe “Federal income tax” line of the bonus pay stub, or the federal withholding on the vesting confirmation.
How this tool treats itIncome tax only: leave out Social Security, Medicare and state tax. Capped at the taxable bonus.
Allowed range$0 to $10,000,000
Filing status
The status you expect to file under for the year the bonus is paid.
How this tool treats itIt sets your tax rates and standard deduction on the return. The withholding on the bonus ignores it under the flat rate, which is one reason the two can differ.
Your yearly salary
Your regular pay for the whole year from the employer paying the bonus, before tax, without the bonus.
Where to find itYour offer letter or a recent pay stub (pay per period × pay periods).
How this tool treats itThe bonus is taxed on your return at the rates that apply on top of your salary and other income: your marginal rate, not 22%. A bonus that crosses into a higher bracket is taxed at each rate for the part inside that bracket.
Allowed range$0 to $10,000,000
Your spouse’s yearly wages
Your spouse’s wages for the year, on a joint return.
Where to find itTheir Form W-2, box 1 (or their pay stubs).
How this tool treats itThey raise the rates your bonus is taxed at on a joint return. They also count toward the Additional Medicare Tax: 0.9% of Medicare wages over $250,000 on a joint return, $125,000 on a separate one and $200,000 otherwise. Employers withhold it only on their own pay over $200,000, so a couple can owe it with none withheld.
Allowed range$0 to $10,000,000
Your spouse’s pre-tax contributions from pay
What your spouse puts into a 401(k), 403(b) or 457(b) from pay over the year, before tax, on a joint return.
Where to find itTheir pay stub, or their Form W-2 box 12.
How this tool treats itTheir wages for income tax leave these out, but their Medicare wages include them, so they count toward the Additional Medicare Tax on your joint return.
Allowed range$0 to $100,000
Social Security benefits this year
The Social Security benefits you (and your spouse, on a joint return) receive this year, if any.
Where to find itForm SSA-1099, box 5.
How this tool treats itUp to 85% of benefits are taxable, depending on your other income. A bonus raises that income, so it can make more of your benefits taxable, and the tax it adds then runs above your bracket rate. On a separate return the tool assumes you lived with your spouse at some time in the year, which makes more of the benefits taxable.
Allowed range$0 to $500,000
How often you’re paid
Your regular pay schedule.
How this tool treats itUsed only for the “added to a paycheck” method: the withholding tables treat each paycheck as a year of pay at that rate, so a bonus on a weekly check is withheld differently from one on a monthly check.
Regular pay received before the bonus
The regular pay this employer has already paid you this year, before the bonus.
Where to find itThe year-to-date gross pay on your latest pay stub, less any earlier bonuses.
How this tool treats itSocial Security tax stops for the year once your pay from one employer reaches the wage base. If you are near it, the bonus check pays Social Security only up to the base. Over the whole year the bonus adds Social Security tax only up to the base, however its timing falls; the tool shows both.
Allowed range$0 to $10,000,000 (read as no more than your salary)
Earlier bonuses this year
Bonuses and other supplemental pay this employer has already paid you this year.
Where to find itYour year-to-date pay stub.
How this tool treats itOnce an employee’s supplemental pay from one employer (businesses under common control count as one) passes $1,000,000 in a calendar year, the employer must withhold 37% on the part above it, whatever the W-4 says and whichever method it uses. Earlier bonuses count toward the $1,000,000.
Allowed range$0 to $10,000,000
Pre-tax contributions from your salary
What you put into a 401(k), 403(b) or 457(b) from your salary over the year, before tax.
Where to find itYour pay stub (each period’s contribution × pay periods), or Form W-2 box 12.
How this tool treats itThey lower your taxable pay but not your Social Security and Medicare wages. Leave out Roth contributions, which are taxed now.
Allowed range$0 to $100,000
Pre-tax contributions from the bonus
The amount your plan takes from this bonus into a 401(k), 403(b) or 457(b), if it takes any.
Where to find itYour plan’s rules on bonuses, or the bonus pay stub.
How this tool treats itIt is not taxed or withheld on now (Social Security and Medicare still apply), and it lowers the supplemental pay counted toward $1,000,000. The tool does not check the year’s contribution limit.
Allowed range$0 to $100,000 (no more than the bonus)
Interest, ordinary dividends and other income
Other taxable income on your return taxed like wages: interest, nonqualified dividends, short-term gains and anything else.
Where to find itForms 1099-INT and 1099-DIV, or last year’s return as a guide.
How this tool treats itAll of it is treated as investment income for the 3.8% net investment income tax, which applies to the smaller of that income and your income above $250,000 (joint), $125,000 (separate) or $200,000 (otherwise). A bonus can start or raise it.
Allowed range$0 to $10,000,000
Qualified dividends and long-term gains
Qualified dividends and gains on investments held more than a year.
Where to find itForm 1099-DIV box 1b and Form 1099-B.
How this tool treats itTaxed at 0%, 15% or 20%, stacked on top of your other income, so a bonus can push some of them into a higher rate.
Allowed range$0 to $10,000,000
Adjustments to income
Deductions that come before adjusted gross income: deductible IRA and HSA contributions you make yourself, educator expenses. The amount is held fixed, so a deduction that shrinks as income rises (student loan interest, or a deductible IRA when you have a workplace plan) can cost a little more tax than shown.
Where to find itSchedule 1 (Form 1040), Part II.
Allowed range$0 to $1,000,000
Itemized deductions
Your total itemized deductions, if you itemize.
Where to find itSchedule A (Form 1040).
How this tool treats itThe larger of this and the standard deduction is used, on both returns.
Allowed range$0 to $10,000,000
Children under 17
The number of children you can claim who are under 17 at the end of the year.
How this tool treats itEach brings the child tax credit. It shrinks by $50 for each $1,000 (or part of $1,000) of income above $400,000 on a joint return or $200,000 otherwise, so a bonus can cost some of it. Part of the credit can be refunded, and a bonus can raise that part for a lower earner. Assumes each child, and you, have a Social Security number valid for work.
Allowed range0 to 10
Other dependents
Dependents who are not children under 17, such as an older child or a parent.
How this tool treats itEach brings the $500 credit for other dependents, phased out with the child tax credit.
Allowed range0 to 10
65 or older
Tick if you (and, on a joint return, your spouse) will be 65 or older at the end of the year.
How this tool treats itIt adds to the standard deduction and, for 2025 through 2028, brings the senior deduction of up to $6,000 a person, reduced by 6% of income above $75,000 ($150,000 joint), so a bonus can shrink it.
Your Form W-4
What your current Form W-4 says: Step 1(c) filing status, the Step 2 box, Step 3 credits and Step 4(a) and 4(b) amounts.
Where to find itThe W-4 you gave your employer, or your payroll portal’s tax settings.
How this tool treats itUsed only for the “added to a paycheck” method, which runs Pub. 15-T’s percentage method on the paycheck with the bonus and without it. Step 4(c) extra withholding is left out because it is added to both and cancels. A W-4 from 2019 or earlier (allowances) is not covered.
Paychecks left this year after the bonus
How many regular paychecks you have left this year, if you want to spread a shortfall over them.
How this tool treats itThe tool divides the shortfall by them, rounded up to the dollar: the extra amount to enter in Step 4(c) of a new W-4. Withholding counts as paid evenly through the year, so extra withholding in December avoids an underpayment penalty as well as an earlier payment would.
Allowed range0 to 52
Questions
Are bonuses taxed at a higher rate than salary?
Why was so much withheld from my bonus?
Why wasn’t 22% enough?
Can I ask my employer to withhold more from my bonus?
How are RSUs taxed when they vest, and what is my cost basis?
Can my employer always use the flat 22%?
Does a 401(k) contribution from my bonus lower the tax?
Will I owe a penalty if the withholding was short?
Is my bonus taxed by my state?
Version history
- October 10, 2026 (version 1.0.0): First version: federal withholding on a bonus or RSU vest (flat 22%, 37% over $1 million, or added to a paycheck), Social Security and Medicare, and what the bonus adds to your 2025 or 2026 return.