Raffle Win Probability Calculator
Wondering what your real chance of winning a raffle is? Enter how many tickets you hold, the total number of tickets sold, and how many prizes will be drawn. The calculator returns the exact probability that you win at least one prize, the probability you win nothing, and the expected number of prizes you take home. It assumes prizes are drawn without replacement, the standard raffle rule where each ticket can win at most once. The result is an exact probability, with no estimation or assumption beyond a fair, random draw.
Raffle probability formula
Let N = total tickets, y = your tickets, m = prizes drawn
P(win nothing) = product over i from 0 to m-1 of (N - y - i) / (N - i)
P(win at least one) = 1 - P(win nothing)
Expected prizes = m * y / N
Each factor is the chance that a given draw, conditioned on the earlier draws, picks one of the other tickets rather than yours. Multiplying them gives the probability you avoid every prize.
How to interpret your odds
- Your odds scale with your share of the total tickets sold.
- More prizes drawn raises your chance of winning at least one.
- The expected prizes figure can be less than 1 even when winning is likely, since most wins are a single prize.
- If your tickets equal the total, you are guaranteed to win every prize (probability 1).
- This model assumes a fair draw with each remaining ticket equally likely at every step.
Raffle win probability: frequently asked questions
How is raffle win probability calculated?
When prizes are drawn without replacement, the chance you win nothing is the product over each draw that your tickets are not selected. The chance of winning at least one prize is 1 minus that product. This calculator uses the exact hypergeometric form for drawing without replacement.
What does drawing without replacement mean?
It means each ticket can win at most one prize: once a ticket is drawn it is set aside. This is how most physical raffles work. The probability of avoiding all prizes is (N - y)/N times (N - 1 - y)/(N - 1) times ... across the number of prizes drawn, where N is total tickets and y is your tickets.
Does buying twice as many tickets double my odds?
It roughly doubles your odds when your share is small, but not exactly, because the probability of winning at least one prize is capped at 1 and the relationship is not perfectly linear. The calculator computes the exact figure for any ticket count.
What is the expected number of prizes I win?
By linearity of expectation, the expected number of prizes you win equals the number of prizes drawn times your share of tickets (y divided by N). This holds whether prizes are drawn with or without replacement.
What inputs are required?
Enter your number of tickets, the total number of tickets sold, and the number of prizes drawn. Your tickets cannot exceed the total, and the prizes drawn cannot exceed the total tickets. Invalid combinations return n/a.
Official sources
- NIST/SEMATECH e-Handbook of Statistical Methods: Hypergeometric distribution.
- NIST Digital Library of Mathematical Functions: Combinatorial functions.
Reviewed by the CalculatorHub team, edited by James Graham, 16 June 2026. See our methodology.