2026 Bonus tax calculator

How bonus withholding works in 2026

This models the optional 22% method for separately identified supplemental pay when regular wages had income-tax withholding this year or last year. Supplemental pay above a cumulative $1 million uses 37%; include commonly controlled businesses. Payroll may use an aggregate method instead. IRS Publication 15, section 7.

Employee Social Security withholding is 6.2% through $184,500 in 2026, and Medicare is 1.45% without a wage cap. An employer withholds another 0.9% on Medicare wages above $200,000, regardless of filing status. IRS Publication 15, section 9 and SSA contribution base.

Worked examples

A $10,000 bonus with $50,000 prior Social Security and Medicare wages and no earlier supplemental pay has $2,200 income-tax withholding, $620 Social Security and $145 Medicare. The modeled federal net is $7,035. For a single filer with $75,000 full-year ordinary income excluding the bonus and a $16,100 deduction, annual income tax rises from $7,670 to $9,870: an increase of $2,200.

With $180,000 prior Social Security wages, only $4,500 of that same bonus remains subject to Social Security: $279 withheld. With $195,000 prior Medicare wages, $5,000 crosses the Additional Medicare threshold: another $45 withheld. At $995,000 earlier supplemental pay, a $10,000 bonus has $2,950 income-tax withholding ($5,000 at each rate).

Withholding versus annual tax

Withholding prepays your income tax. The annual comparison applies the 2026 ordinary-income brackets before and after adding the bonus, holding your chosen deduction constant. A difference is not a predicted refund; it excludes credit changes, AMT, preferential capital-gain rates and final payroll-tax reconciliation. IRS Publication 505 explains withholding and estimated tax.

Scope and source notes

The bonus must be fully taxable ordinary wages subject to both Social Security and Medicare. State/local taxes, retirement contributions, benefits and employer-paid taxes are excluded. The annual comparison excludes income-dependent deduction phaseouts; enter an appropriate custom deduction for age, blindness or itemizing. It holds that deduction constant with and without the bonus.

Use separate Social Security and Medicare wage figures if your pay stub shows different taxable bases. Multiple employers can cause Social Security overwithholding and final Additional Medicare tax differences. This tool models the paying employer's withholding only.

Source amounts: IRS Revenue Procedure 2025-32 for 2026 brackets/deductions. Publication 15-T covers payroll methods; this tool does not implement those aggregate tables. All calculator assumptions and sources.