Guide
Why Is My Bonus Taxed So Much?
Because it almost certainly wasn't. Your bonus was withheld at a flat rate, not taxed at a higher one — and those are two genuinely different things. For most people the flat rate takes out more than they'll actually owe, and the excess comes back at tax time. Here's what happened to your money.
Withholding is a deposit, not a bill
Every dollar your employer holds back is an estimated prepayment toward a tax bill nobody can calculate until the year is over. Your actual tax is worked out once, in April, on your total income for the year. Everything withheld before then is just money sent ahead.
So when a bonus arrives looking mauled, the right question isn't "why was it taxed so much?" It's "was too much withheld?" — and if the answer is yes, the difference isn't gone. It's sitting with the IRS waiting to be reconciled.
The flat 22%
The IRS treats bonuses as supplemental wages — money outside your regular salary, a category that also covers commissions, severance, back pay, and payouts for unused vacation. When an employer identifies supplemental wages separately from regular pay, they're allowed to skip the normal withholding tables and apply one flat rate.
For 2026 that rate is 22%. It applies no matter what you earn, until supplemental wages cross $1 million in a single calendar year, at which point the amount above that is withheld at 37%.
Notice what the 22% is not. It isn't a bonus tax — no such thing exists. It isn't your tax bracket. It's a single flat percentage applied to everyone from the newest hire to the most senior executive, precisely because it's a placeholder rather than a calculation.
Why it felt like half
Federal withholding is only one line on the stub. Here's a $10,000 bonus with everything taken out, assuming a 5% state income tax:
Total withheld −$3,465 · Lands in your account: $6,535
About 35% gone, which is where "my bonus got taxed at 40%" comes from. But only the $2,200 is a federal estimate. The Social Security and Medicare pieces are real and final — you owe those on every dollar you earn, bonus or not, and they don't come back. Social Security stops once your wages pass $184,500 for the year; Medicare never stops.
If you live somewhere with no state income tax, delete that $500 line and roughly 30% comes out instead.
Whether you actually overpaid
This is the part that decides your outcome, and it comes down to one comparison: the flat 22% against your real marginal rate. Three single filers, using the 2026 brackets and the $16,100 standard deduction.
Earning $45,000, with a $5,000 bonus. The bonus lands entirely inside the 12% bracket, so its true federal tax is $600. Withheld: $1,100. Overpaid by $500, which comes back as a refund.
Earning $65,000, with a $10,000 bonus. The bonus straddles the 12% and 22% brackets, giving it a true tax of $2,050. Withheld: $2,200. Overpaid by $150. Close to a wash.
Earning $150,000, with a $20,000 bonus. Now the bonus sits in the 24% bracket, so its true tax is $4,800. Withheld: $4,400. Underpaid by $400 — this person owes slightly more in April.
The pattern is worth internalizing: if your top bracket is below 22%, the flat rate over-withholds and you get money back. If it's above 22%, the flat rate under-withholds and you should expect a slightly larger bill. The people most convinced their bonus was overtaxed are usually the ones getting a refund for it.
The other method, and why your coworker's math differs
Employers have a second option: the aggregate method. Instead of separating the bonus out, they lump it into a regular paycheck and run the whole amount through the normal withholding tables.
This one can look far worse. The tables assume every paycheck is typical — so a check containing your salary plus a bonus gets treated as though you earn that much every single pay period, projecting you into brackets you'll never actually reach. Withholding on that check can be brutal.
It corrects itself completely at tax time, because your annual return doesn't care how any individual check was withheld. But it explains why two people at the same company with identical bonuses sometimes see very different take-home. Different employers, different methods.
What you can actually do
You can't opt out of supplemental withholding — the method is your employer's choice, not yours. What you can do is stop the surprise from mattering.
If you consistently get large refunds, you're lending the government money at 0% for a year. Adjusting your W-4 puts that money in your paychecks instead. If you're a higher earner who reliably owes because 22% under-withholds your bonuses, the extra-withholding line on your W-4 lets you cover the gap in advance rather than writing a check in April.
Either way, the fix is the W-4, not the bonus.
The one thing worth checking on the stub
When the bonus arrives, look at the year-to-date columns rather than just the current-period ones. Two things go wrong often enough to be worth ten seconds: Social Security continuing to be withheld after your wages have passed $184,500, and a 401(k) contribution either taken from the bonus when you didn't expect it or skipped when you did. Plans differ on whether bonuses are eligible for deferral, and payroll systems get it wrong.
Our guide to reading your pay stub walks through every line if you want to check the rest while you're there.
Worth noting. This is general education, not tax advice, and it covers federal rules — state supplemental withholding varies, and some states apply their own flat rate. For your specific situation, particularly if a bonus is large relative to your salary, talk to a qualified tax professional.