Compare the flat method and aggregate method for bonus withholding
How much of your bonus you keep
Combined paycheck with bonus
Combined paycheck breakdown
What changed because of the bonus
This calculator provides estimates for informational purposes only. Results are not guaranteed to be accurate for every individual's tax situation. Consult a tax professional for advice specific to your situation. Tax rates and brackets are based on 2026 federal and state guidelines.
Questions people ask before they run the numbers
What is the flat bonus withholding method?⌄
It applies the federal supplemental wage rate directly to the bonus, then layers in state withholding and FICA for a quick estimate.
When is the aggregate method more useful?⌄
The aggregate method is helpful when a bonus is paid with regular wages in the same check and payroll wants to compare total withholding with and without the bonus included.
Why can the flat method and aggregate method be different?⌄
The flat method uses a fixed federal percentage, while the aggregate approach can push part of the bonus into higher withholding because it compares total annualized income with and without the extra pay.
Does this calculator include Social Security and Medicare?⌄
Yes. Both bonus methods include Social Security and Medicare in the estimate so you can see a realistic net amount.