Windfall Tax Calculator: What You Actually Keep
Example: Windfall amount (gross): 100000 $ · Windfall type (1=Bonus/RSU, 2=Lottery, 3=Inheritance): 1 · Other income this year: 75000 $ · Filing status (0 = Single, 1 = Married Filing Jointly): 0
| What you actually keep | $72,614 |
| Total estimated tax | $27,386 |
| Federal income tax on windfall | $23,386 |
| Effective rate on windfall | 0.27% |
Worked example
A $100,000 year-end bonus on top of $75,000 salary pushes total income to $175,000 (single filer, 2026 brackets). The bonus does not get taxed at one rate: it fills the rest of the 22% band and then runs into the 24% band, which for 2026 starts at $105,700. The incremental federal tax works out to about $23,386, plus an estimated $4,000 in state taxes. Net take-home: approximately $72,614 — not $100,000. Knowing this before spending prevents a surprise tax bill in April.
Frequently asked questions
Why does my employer withhold only 22% on my bonus?
The IRS supplemental wage withholding rate is a flat 22% for amounts under $1 million. But your true marginal rate may be 24%, 32%, or 35% depending on your total income. The 22% withholding is a deposit — your actual tax bill is settled at filing.
Is inheritance taxable at the federal level?
Most beneficiaries pay zero federal income tax on inherited assets. The estate pays any federal estate tax owed, and the exemption is $15 million per person for 2026 — set at that level and made permanent by the One Big Beautiful Bill Act, so the sunset to roughly $7 million that older guidance warns about did not happen. However, six states impose an inheritance tax on beneficiaries; the tool adds an average estimate to flag this. Consult a tax professional for state-specific amounts.
How is lottery income taxed differently from a bonus?
Both are ordinary income, but the IRS mandates 24% federal withholding on lottery prizes over $5,000. Your final bill is still based on your total taxable income for the year — the withholding is just an advance. Large lottery wins can push you into the 37% bracket, meaning you owe more at filing.
Does this calculator include FICA (Social Security and Medicare) taxes?
This tool focuses on income tax. FICA taxes (6.2% Social Security up to the $184,500 wage base for 2026, 1.45% Medicare with no cap, plus 0.9% Additional Medicare Tax above $200,000 single — that $200,000 is statutory and has never been indexed, so do not expect it to move) may also apply to bonuses and RSU income — add roughly 7.65% to your total cost if you are under the wage base.