How to calculate bonus after tax in 2026

A separate bonus check can feel confusing because it is usually withheld differently from regular wages. The check may show a big federal tax line even when your year-end tax rate is lower. That does not always mean the bonus is taxed at a special final rate; it usually means payroll used a supplemental wage withholding method.

This walkthrough shows a practical way to estimate a 2026 bonus after tax before payday.

1. Start with the gross bonus

Use the bonus amount before any deductions. For example, assume a $5,000 bonus paid as a separate check.

2. Estimate federal supplemental withholding

For many separate bonus checks, employers use the flat supplemental wage method. In 2026, the common federal supplemental withholding rate is 22% for supplemental wages up to $1 million.

Example:

$5,000 bonus x 22% = $1,100 federal withholding

If the bonus is paid with regular wages in the same paycheck, payroll may instead use the aggregate method. That method combines regular wages and bonus wages, applies the regular withholding tables, then subtracts the withholding already attributable to regular wages. The result can be higher or lower than the flat method depending on pay frequency, W-4 settings, and current earnings.

3. Add FICA taxes

Bonuses are wages for Social Security and Medicare purposes.

A quick employee-side estimate is:

Social Security: 6.2% up to the annual wage base

Medicare: 1.45%

Total FICA: 7.65% for most bonus checks

On a $5,000 bonus, FICA is usually about:

$5,000 x 7.65% = $382.50

High earners may also run into wage base limits or additional Medicare withholding, so the exact answer depends on year-to-date wages.

4. Include state and local withholding

This is where estimates often drift. Some states use flat bonus withholding rates, some use regular wage tables, and some have local payroll taxes. A bonus in New York City, Ohio, Pennsylvania, or Illinois can produce a different take-home result even when the gross bonus is identical.

A simple worksheet is:

Gross bonus

- federal supplemental withholding

- Social Security

- Medicare

- state withholding

- local withholding

= estimated bonus take-home pay

5. Compare flat vs aggregate method

If payroll uses the flat method, the federal withholding line is easy to approximate. If payroll uses the aggregate method, the answer depends on your regular paycheck, filing status, W-4, pre-tax deductions, and pay schedule.

That is why two employees with the same $5,000 bonus can see different net bonuses.

6. Use a calculator for the final pass

For a faster estimate, I built a free 2026 bonus tax calculator that lets you model a separate bonus check with federal supplemental withholding, FICA, state pages, and methodology notes.

It is still only an estimate. Your final tax for the year is reconciled when you file, and payroll systems can vary by employer setup. But it is a useful planning number before you decide how much of a bonus to save, invest, or use for expenses.