US Bonus Tax Calculator
Estimate the cash left from a bonus using the optional federal flat withholding method. Enter earlier wages to account for the Social Security cap.
Rule year: 2026 · USD · Sources checked
Estimated bonus take-home under flat withholding
One employer; the bonus is separately identified and eligible for optional flat withholding. Earlier wages share the same Social Security and Medicare base. No pre-tax benefit deductions, local taxes, aggregate withholding method or tax-return reconciliation. State withholding is your supplied rate.
For informational purposes only. This estimate is not financial advice, a tax return, a payroll calculation or a lender decision. See the supported circumstances and exclusions below.
How this calculator works
A separately identified supplemental payment can use optional flat federal withholding when the IRS conditions are met. The first $1 million of annual supplemental wages uses 22%; excess uses 37%. Employee Social Security applies only to wages below the annual covered-earnings cap. Medicare continues above that cap, and an employer starts Additional Medicare withholding above $200,000 of wages. The result is a cash-withholding illustration: your actual income-tax liability depends on the full return.
Formula and rules
Federal withholding = eligible lower slice × 22% + slice above $1 million × 37%. Net bonus = bonus − federal withholding − employee payroll withholding − entered state withholding.
Assumptions and limitations
One employer; the bonus is separately identified and eligible for optional flat withholding. Earlier wages share the same Social Security and Medicare base. No pre-tax benefit deductions, local taxes, aggregate withholding method or tax-return reconciliation. State withholding is your supplied rate.
Worked example
A $10,000 bonus with $60,000 of earlier covered wages and no state withholding has $2,200 federal withholding and $765 employee payroll withholding. The estimated cash payment is $7,035.
- Estimated bonus take-home under flat withholding
- $7,035.00
- Federal supplemental withholding
- $2,200.00
- Social Security withholding
- $620.00
- Medicare withholding
- $145.00
Official sources and review
Reviewed against the sources below on 2026-10-06. Rates are held in versioned rule modules. Versioned rules, official source review and year-specific calculation tests.
- IRS Publication 15 (2026) ↗
Optional flat supplemental withholding of 22%, with 37% above $1 million of annual supplemental wages; eligibility conditions apply.
- IRS: Social Security and Medicare withholding ↗
Employee Social Security 6.2%, Medicare 1.45%; employer Additional Medicare withholding starts above $200,000.
- SSA: Contribution and benefit base ↗
2026 covered-earnings cap: $184,500.
- IRS: Additional Medicare Tax ↗
0.9% additional tax and filing-status thresholds; withholding and final liability differ.
Common questions
Is the 22% rate the tax I ultimately owe on my bonus?
It is an optional withholding rate. Your full-year federal income-tax calculation may produce a higher or lower liability.
Why does earlier pay change the result?
Earlier wages use part of the Social Security cap and can trigger Additional Medicare withholding. Earlier supplemental pay also affects the $1 million federal threshold.
Can I use this for an aggregate-method bonus?
No. The aggregate method combines wages for payroll-table withholding and needs different inputs. Check which method your employer uses.