Raffle Odds Calculator

Raffle win percent and 1-in-N odds, single or multi-prize.

What it does

Raffle odds are counting, not luck analysis. Five tickets in a 200-ticket drum with one prize win 2.5 % of the time, and three prizes lift ten tickets in a hundred to 27.35 %. Every extra ticket and every extra prize moves the number by exact arithmetic.

The tool above prices single and multi-prize draws. Enter tickets held, total sold, prize count, and an optional jackpot, and it prints win percent, 1-in-N odds, and expected value. Defaults give 2.5 %, 1 in 40, and $25.00 expected on a $1,000 prize.

Probability courses teach the same counting. MIT OCW probability syllabi cover hypergeometric distributions for draws without replacement, and AMS lottery analysis applies the identical combinatorics to public games. The multi-prize form here is one minus the miss-all product across draws.

Expected value prices the ticket, not the dream. A $25 EV on $5 of tickets is a fine flutter; the same EV on $50 of tickets is a donation. Compare EV against cost, cap entertainment spending, and never chase losses across raffles.

How to use

Enter tickets you hold.
Enter total tickets sold.
Enter the prize count.
Enter the jackpot for EV, else 0.
Read win percent first, then 1-in-N.
Compare EV against the ticket cost.

Formula

Single: P = held/total. Multi: P = 1 minus product((N-k-i)/(N-i)) over prizes. Odds 1 in total/held equivalent. EV = P x jackpot.

held: Your tickets, 1 and up.
total: All tickets sold, held and up.
prizes: Prizes drawn without replacement, 1 and up.
jackpot: Prize value for EV math, 0 skips EV.

Multi-prize form is 1 minus hypergeometric P(zero wins). MIT OCW covers hypergeometric distributions; AMS covers lottery probability analysis.

Worked example

Example: 5 of 200, one prize

Defaults: 5 of 200 tickets, 1 prize, $1,000 jackpot.

Inputs: 5 of 200 tickets, 1 prize, $1,000 jackpot.
Chance: 5 / 200 = 0.025 = 2.5 %.
Odds: 200 / 5 = 1 in 40.
Value: 0.025 x 1,000 = $25.00 expected.
Tool shows 2.5%, 1 in 40, $25.00 expected.

Reference table

Raffle odds checks
Held / Total	Prizes	Win
1 / 100	1	1.00 %, 1 in 100
5 / 200	1	2.50 %, 1 in 40
2 / 50	1	4.00 %, 1 in 25
5 / 50	2	19.18 %, 1 in 5.21
10 / 100	3	27.35 %, 1 in 3.66
10 / 100	1	10.00 %, 1 in 10

Limits

Fair draws assumed. Weighted drums break the math.
Ignores ticket cost in odds; EV needs the jackpot.
Prizes capped at 500 draws for compute safety.
Shared prizes split value outside this page.

Common mistakes

Reading 1 in 40 as 40 %.
Forgetting extra prizes lift odds a lot.
Pricing tickets by jackpot instead of EV.
Chasing losses across raffles.
Trusting lucky number patterns.

Try it yourself

Quick checks. Answers sit tucked under each question.

10 of 100 tickets, 3 prizes?

Miss (90x89x88)/(100x99x98) = 0.72653. Win 1 minus that = 27.35 %. 1 in 3.66.

5 of 50 tickets, 2 prizes?

Miss (45x44)/(50x49) = 0.80816. Win 19.18 %. 1 in 5.21.

Questions

How are single-prize odds figured?

Held over total times 100. Five of 200 is 2.5 %, or 1 in 40.

How do multi-prize draws work?

One minus the miss-all product over draws. Ten of 100 over 3 prizes is 27.35 %.

What is expected value?

Chance times jackpot. Here 0.025 x $1,000 = $25.00 expected value.

How do 1-in-N odds follow?

Total over held: 200/5 = 40. The percent and the 1-in-N say the same thing.

Do extra buyers hurt me?

No. More tickets always raise the chance here, unlike pari-mutuel pools splitting fixed prizes.

Are draws assumed fair?

Yes. This page assumes fair draws without replacement; rigged or weighted draws break the math.

Sources

How this page was checked. The formula above was matched against the cited sources, and the worked example was run through the tool on this page before publishing. If you spot an error, contact us so we can fix it and note the correction.