This Taxable Bonus Calculator estimates how much of a one-time bonus you will actually receive after mandatory withholdings: federal withholding, state tax, Social Security, Medicare, and any additional flat or pre-tax reductions (like a 401(k) deferral). It is commonly used by payroll teams and employees to forecast take-home pay from supplemental wages.
Bonuses are generally treated as supplemental wages. Employers may withhold using the IRS supplemental flat rate (commonly 22% in the U.S. for most bonuses under $1,000,000) or by aggregating the bonus with regular wages and applying the employee's regular withholding. This calculator lets you model both approaches by changing the federal rate input.
Conceptually the taxable portion of a bonus is:
$$\text{TaxableAmount} = \max(0, \text{GrossBonus} - \text{PreTaxDeductions} - \text{OtherDeductions})$$
Then compute each withholding component (using rates as decimals):
$$\text{FederalWithheld} = \text{TaxableAmount} \times f$$
$$\text{StateWithheld} = \text{TaxableAmount} \times s$$
$$\text{SocialSecurity} = \text{TaxableAmount} \times ss$$
$$\text{Medicare} = \text{TaxableAmount} \times m$$
Finally net bonus (take-home) is:
$$\text{NetBonus} = \text{TaxableAmount} - (\text{FederalWithheld} + \text{StateWithheld} + \text{SocialSecurity} + \text{Medicare} + \text{AdditionalWithholding})$$
Example: You receive a $10,000 bonus. You elect a $1,000 401(k) pre-tax deferral. Using the default rates (Federal 22%, State 5%, SS 6.2%, Medicare 1.45%):
$$\text{TaxableAmount} = 10{,}000 - 1{,}000 = 9{,}000$$
Withholdings:
$$\text{FederalWithheld} = 9{,}000 \times 0.22 = 1{,}980$$
$$\text{StateWithheld} = 9{,}000 \times 0.05 = 450$$
$$\text{SocialSecurity} = 9{,}000 \times 0.062 = 558$$
$$\text{Medicare} = 9{,}000 \times 0.0145 \approx 130.50$$
$$\text{NetBonus} \approx 9{,}000 - (1{,}980 + 450 + 558 + 130.50) \approx 4{,}881.50$$
| Method | Federal Rate Used | Estimated Net Take-Home (from $10,000) |
|---|---|---|
| Supplemental Flat Rate | 22% | $4,882 (approx) |
| Aggregate with Regular Pay (Higher Effective Rate) | 32% (example) | $3,682 (approx) |
| Low Federal Withholding (10%) | 10% | $6,282 (approx) |
The IRS commonly prescribes a flat supplemental withholding rate (22% as of recent guidance) for bonuses treated as supplemental wages. Employers may instead compute withholding by aggregating wages.
Employers set payroll withholding procedures based on tax law and company policy. You can ask payroll about changing withholding or electing pre-tax 401(k) deferrals to reduce taxable bonus amount.
Possibly. Withholding is an estimate. If your total annual tax liability exceeds cumulative withholding, you may owe at filing. Conversely, over-withholding results in a refund.
This tool models federal, state, Social Security, and Medicare as percentage-based estimates. It does not automatically apply municipality taxes or Social Security wage-base caps; adjust inputs to reflect local or year-to-date limits.