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Lottery Calculator

Methodology

How the Lottery Calculator tools produce their numbers — what each one computes, the assumptions baked into every estimate, where the tax data and game rules come from, and when each source was last verified. No black boxes: if a number appears on this site, this page explains how it was made.

What the calculators compute

  • Tax estimates — estimated federal and state tax on a lottery prize, plus estimated take-home amount and effective tax rate.
  • Payout comparisons — cash option versus annuity, shown side by side as estimates with no recommendation of one over the other.
  • Odds & probability — jackpot odds, odds of any prize, and probability across multiple tickets, derived from each game's official rules.
  • Random number generation — quick-pick style combinations for convenience only. Every combination has exactly the same probability; nothing here predicts winners.

How tax estimates work

  1. Lottery winnings are treated as ordinary income. The calculator subtracts the standard deduction for your filing status (single, married filing jointly, married filing separately, or head of household), then applies that tax year's progressive federal brackets.
  2. State tax is estimated with a top-marginal-rate planning estimate for the selected state and year — a deliberately conservative planning figure, not a simulation of a full state return.
  3. States that do not tax lottery winnings (for example California, which exempts California Lottery winnings, and states with no individual income tax) show $0 state tax.
  4. Estimated federal and state taxes are added for the total estimated liability; subtracting it from the prize gives the estimated take-home amount and effective tax rate.

Federal withholding is kept separate from estimated liability throughout the site. Withholding (24% on gambling winnings over $5,000) is what may be held back when you are paid — it is credited against your final tax bill, not added to it. West Virginia is currently flagged as needing verification because a reported 2026 rate change is not yet confirmed against an authoritative source.

How payout estimates work

The cash option is never invented — you always enter the current cash value yourself, because only the lottery publishing the jackpot knows it. For the annuity, each annual payment is taxed in the year it is received:

  • Powerball: 30 graduated payments over 29 years. No verified fixed growth rate is published, so you enter the growth rate — the default is clearly labeled as an assumption.
  • Mega Millions: one immediate payment followed by 29 annual payments, each 5% larger than the last, per the official game rules.

The site shows cash and annuity estimates side by side and never says one choice is better than the other.

How odds are calculated

All odds come from the combinatorics of each game's official matrix — for example, Powerball's 5-from-69 plus 1-from-26 and Mega Millions' 5-from-70 plus 1-from-24. Jackpot totals are derived from the centralized game configuration at build time, never hard-coded. Multi-ticket probability uses the standard 1 − (1 − p)^n formula under the documented assumption that each ticket is an independent draw.

How the number generator works

Combinations are drawn with the WebCrypto API (a partial Fisher–Yates shuffle with rejection sampling), falling back to Math.random only if WebCrypto is unavailable. Main numbers are sorted, bonus balls are drawn separately, duplicates are removed by default, and requests are capped at 100 sets. Generated sets are for convenience only — the generator makes no prediction, and no "hot", "cold", or "due" numbers exist. Nothing is stored, tracked, or sent anywhere.

Limitations

  • Every figure on this site is an estimate, not tax or financial advice.
  • State figures are planning-rate estimates; local and city taxes are not included.
  • Your actual tax bill depends on your full return and the laws in effect when you claim.
  • Game rules and tax laws change — verify against the official sources below before acting.

Data sources

  • IRS Revenue Procedure 2025-32 · Internal Revenue Service · Last verified 2026-09-28

  • IRS guidance on withholding for gambling winnings · Internal Revenue Service · Last verified 2026-09-28

  • State Individual Income Tax Rates and Brackets, 2026 · Tax Foundation · Last verified 2026-09-28

  • California Lottery winnings exemption · State of California (Franchise Tax Board / California Lottery) · Last verified 2026-09-28

  • Washington State Department of Revenue guidance · Washington State Department of Revenue · Last verified 2026-09-28

  • New Hampshire Department of Revenue Administration · State of New Hampshire · Last verified 2026-09-28

  • West Virginia SB 392 (2026 session) — unverified · West Virginia Legislature · Last verified 2026-09-28

  • Powerball official game rules · Multi-State Lottery Association (MUSL) · Last verified 2026-09-28

  • Powerball prize tiers and odds · Multi-State Lottery Association (MUSL), corroborated by lotteryusa.com and powerball.net · Last verified 2026-09-28

  • Mega Millions official how-to-play · Mega Millions Consortium · Last verified 2026-09-28

  • Mega Millions prizes and odds table · Mega Millions Consortium · Last verified 2026-09-28

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