Methodology and sources
Every figure on the site is computed by code from published brackets and rules, and every worked example is computed twice, band by band and from a cumulative table, and published only when both agree to the cent.
Sources
- Federal brackets and standard deductions for 2026: IRS, tax year 2026 inflation adjustments.
- Form W-2G thresholds, 24% regular and backup withholding: IRS, Instructions for Forms W-2G and 5754 (01/2026).
- The 90% limit on gambling losses from 2026: IRC section 165(d) as amended by the One Big Beautiful Bill Act, and the Tax Foundation's analysis.
- State brackets and standard deductions for 2026: Tax Foundation, state individual income tax rates and brackets, 2026.
How the tax on a win is computed
The tax a win adds is your tax with the win minus your tax without it, both with the 2026 brackets for your filing status. Your deduction is the larger of the standard deduction and your itemized deductions; gambling losses are itemized at 90% of their amount and never above the winnings. State tax works the same way with the state's brackets and standard deduction; losses are not deducted for state tax.
The lottery calculator splits the advertised jackpot into 30 yearly payments, each 5% larger than the one before, and taxes every payment in its own year with the 2026 brackets. It also finds the yearly return at which the after-tax annuity is worth the after-tax lump sum.
What is left out
- Local income taxes, such as New York City and Yonkers.
- State personal exemptions and credits, and the recapture of lower brackets at high incomes in New York and Connecticut.
- Other deductions, credits, the alternative minimum tax and the net investment income tax.
- Tax in a second state where a non-resident won, and the credit for it at home.
- Future changes to brackets and law, which will change the tax on later annuity payments.
Tell us about an error through the contact page; corrections are dated on the page.
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