Bonus Withholding Calculator
For bonus-season paychecks.
The short answer: At the scenario numbers pre-loaded below, the OBBBA deductions total $3,625, worth about $798 in federal income tax at a 22% marginal rate ($31 per biweekly paycheck) — that's the gap your W-4 can capture during the year.
⚠️ This calculator provides estimates for informational and educational purposes only. It is not tax advice. Results are based on the One Big Beautiful Bill Act (OBBBA) and IRS Schedule 1-A. Consult a qualified tax professional for your specific situation.
Withholding vs. What You Actually Owe
Bonuses default to 22% supplemental withholding (37% over $1M) — often more than your true rate. Deductions on 4(b) reduce the regular checks to compensate.
- • Supplemental rate ≠ your real bracket
- • 4(b) adjusts the regular stream
- • Reconcile at filing either way
Worked Example
A worker with OT plus a December bonus.
- • Total OBBBA deductions: $3,625
- • Federal income tax savings: $798 at the 22% marginal rate
- • Per biweekly paycheck: $31 — capture it via a W-4 4(b) adjustment instead of waiting for refund season
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Frequently Asked Questions
Why is my bonus taxed at 22%?
Supplemental-wage withholding rules — a default, not your final tax. Deductions and brackets reconcile it on the 1040.
Can OBBBA deductions fix bonus over-withholding?
Partially — they reduce total tax; the 4(b) entry spreads the benefit into regular paychecks.