Raffle Odds Calculator
Calculate the chance of at least one prize when winning tickets are drawn without replacement.
How to use this page
- Enter your data and check the input limits.
- Read the result and the detail table when available.
- Change the inputs to compare scenarios. Calculations run locally in your browser.
What this page does not do: It does not point to numbers to play and does not predict a draw — every draw is independent of the previous ones.
Further reading
Formula
P(X ≥ 1) = 1 − C(N − k, m) / C(N, m) N is the total number of eligible tickets, k is your ticket count and m is the number of winning tickets drawn. Every ticket is equally likely. A drawn ticket is not returned to the pool. One person may win more than once with different tickets.
If an organiser removes all of a person’s tickets after their first win, this model does not apply. Your tickets and the number of prizes cannot exceed the pool. Enter all eligible tickets, not just unsold tickets.
Worked example: 10 tickets out of 100 with one prize gives 10%. With several prizes, multiplying that percentage by the prize count is not the correct probability.
See also
Keno Odds Calculator
Probability of every number of matches in Keno (20 of 70) or any game drawn without replacement — a full table, no payouts.
Lottery Odds Calculator
Exact odds of matching any number of balls in Lotto, Eurojackpot, Keno or your own lottery — as 1 in X and as a percentage.
Lottery Syndicate Calculator
Split a prize by member shares. For equal shares, enter 1 for each member.