Net Bonus
$6,655
Take-Home Rate
Total Tax
$3,345
Federal Withholding
$2,200
IA State Tax
$380
Summary
On a $10,000 bonus with $75,000 salary in Iowa, the flat rate method results in $3,345 total tax (33.45%), leaving you $6,655 net.
Iowa taxes your bonus at a 3.80% marginal state rate, adding $380 in state tax on top of federal withholding and FICA.
The flat rate method withholds a fixed 22% on bonuses up to $1 million. Above $1M, the excess is withheld at 37%. This is the most common method employers use.
The aggregate method combines your bonus with your regular pay, calculates tax on the total using marginal brackets, and subtracts what was already withheld on your salary.
Both methods produce the same federal withholding at your income level.
Bonus withholding is not a separate tax rate — both methods are just withholding approaches. Your actual tax liability is determined when you file your return.
Flat vs Aggregate Method (incl. State Tax)
Method Comparison
7 rows
| Item | Flat Method | Aggregate Method |
|---|---|---|
| Federal Withholding | $2,200 | $2,200 |
| Iowa State Tax | $380 | $380 |
| Social Security | $620 | $620 |
| Medicare | $145 | $145 |
| Additional Medicare | $0 | $0 |
| Total Tax on Bonus | $3,345 | $3,345 |
| Net Bonus | $6,655 | $6,655 |
Estimated federal and Iowa bonus tax withholding. State tax is calculated as marginal tax on the bonus amount. Actual withholding may vary by employer. Not tax advice.