Bonus Tax Calculator
Federal withholding and take home on bonus pay.
What it does
Bonus checks look small because employers must withhold federal income tax at flat supplemental rates instead of your usual bracket math. The check still settles up on the tax return, but payday itself follows its own rule.
The tool above takes the bonus with prior supplemental pay this year from the same employer. It returns federal withholding with take home beside it, splitting 22% and 37% at the $1 million line when the year crosses it.
The default $5,000 bonus with nothing prior withholds $1,100.00 and keeps $3,900.00 at the 22% flat rate. With $999,000 already paid, the same bonus withholds $1,700.00 because $4,000 of it crosses into 37%.
Rates follow IRS Publication 15 employer guidance: 22% on supplemental wages, 37% on the part above $1 million paid to one employee in a calendar year. Both the HTML guide and its PDF state the same line.
How to use
- Enter the gross bonus.
- Enter supplemental already paid this year.
- Read federal withholding first.
- Read take home beside it.
- Check which rate applied.
- Budget state and payroll taxes separately.
Formula
- 22%
- Flat rate while yearly supplemental stays at or under $1M.
- 37%
- Mandatory rate on the part above $1M.
- room
- 1,000,000 minus prior supplemental, floored at zero.
- excess
- Year total minus 1,000,000, when positive.
The $1 million line aggregates all supplemental pay from one employer in the calendar year, and the 37% slice is mandatory under the flat method. Flat 22% also assumes income tax already comes out of regular wages; otherwise the aggregate wage table method applies instead.
Worked example
Example: $5,000 bonus, nothing prior
Defaults: bonus 5000, prior supplemental 0.
- Rate: 5,000 under $1M, so 22%.
- Withholding: 0.22 x 5,000 = $1,100.00.
- Take home: 5,000 - 1,100 = $3,900.00.
- Tool shows $1,100.00, $3,900.00, 22 % flat.
- State, Social Security, and Medicare still apply on top.
Reference table
| Situation | Rate | Note |
|---|---|---|
| Supplemental to $1M | 22% flat | Needs withholding on regular wages |
| Part above $1M | 37% flat | Mandatory on the excess |
| No regular withholding | Wage tables | Aggregate method instead |
Limits
- Federal income only; states differ.
- Social Security and Medicare still apply.
- One employer aggregation; new job resets.
- Return reconciles over withholding later.
Common mistakes
- Reading withholding as the final tax.
- Forgetting the $1M yearly aggregation.
- Mixing employers into one total.
- Ignoring state withholding on top.
- Expecting bracket math on the stub.
Try it yourself
Quick checks. Answers sit tucked under each question.
$5,000 bonus after $999,000 prior?
$1,700.00 withheld, $3,300.00 kept, split rate.
$100,000 bonus, nothing prior?
$22,000.00 withheld, $78,000.00 kept.
Does state take more?
Yes, state income tax applies separately on top.
Questions
How much tax comes out of a bonus?
Federal withholding runs 22% flat, 37% past $1M a year, plus payroll and state.
Why is my bonus taxed more?
Withholding uses flat supplemental rates, which often exceed your bracket pace.
Do I get it back?
Over withholding reconciles on Form 1040 at filing.
What counts toward $1M?
All supplemental wages from one employer in the calendar year.
New job mid year?
Each employer tracks its own $1M line separately.
Officer or owner bonus?
Same federal math; employment tax details vary, so confirm with payroll.