What this calculator works out
This calculator divides your tickets by the total tickets sold, expressing the result as a percentage, a one-in figure and traditional betting odds.
The three formats say the same thing. Seeing a chance written as odds against often makes it feel different from the same figure written as a percentage, which is worth noticing.
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Before you calculate
- Total tickets means tickets sold, not tickets printed. A raffle that has not sold out gives better odds than the book suggests.
- The calculation covers a single prize. For a raffle with several prizes, use the Competition Entry Odds Calculator.
- It assumes tickets are drawn at random and that every ticket is in the draw.
- Charity raffles are usually bought as a donation rather than as a bet, which changes the question entirely.
A 2% chance is 49 to 1 against. A 50% chance is evens, or 1 to 1. The odds format expands the low end — it makes small differences at long odds look large and compresses differences near certainty. Betting markets use it; probability is easier to reason about as a percentage.
How this calculator works
A ratio expressed three ways:
Probability = your tickets ÷ total tickets
One in = 1 ÷ probability
Odds against = (1 − probability) ÷ probabilityOdds against express how many losing outcomes there are for each winning one, which is why 2% becomes 49 to 1 rather than 50 to 1 — one of the fifty outcomes is the win.
Worked example: ten tickets in five hundred
Using the default figures — 500 tickets in total, 10 of them yours:
- Chance of winning: 2.00%
- That is 1 in 50, or 49 to 1 against
Doubling to 20 tickets gives 4%, or 24 to 1. The chance doubles exactly, which is the useful property of a single-prize raffle — unlike multi-prize draws, buying twice as many tickets really does double your chance. Whether that is worth twice the money depends on the prize and on why you are buying.
Common mistakes
- Using tickets printed rather than sold. Unsold tickets are not in the draw.
- Applying it to a multi-prize raffle. Use the multiple-prize calculation instead.
- Reading odds against as a one-in figure. 49 to 1 is 1 in 50, not 1 in 49.
- Assuming a large raffle has better prizes proportionally. Often the opposite.
- Buying more tickets to recover previous spending. Past tickets do not affect future draws.
Frequently asked questions
Does buying more tickets really help?
In a single-prize raffle, exactly proportionally — ten tickets are ten times better than one. That is unusual; most gambling products do not scale so cleanly. It remains true that ten times a small chance is still a small chance, and that the total spent rises just as proportionally.
Do raffles need a licence?
In Great Britain, small raffles at an event where tickets are sold and drawn on the day are generally exempt. Raffles where tickets are sold in advance, or across a wider public, usually require registration with the local authority or a Gambling Commission licence, with limits on prize values and ticket prices. Organisers should check before selling.
Is a charity raffle good value?
As a bet, generally not — the prize is worth far less than the tickets sold, which is the point, since the difference funds the charity. As a donation with a small chance attached, it is a reasonable thing to buy. The distinction matters mainly for how much you buy.
Does the order tickets are drawn matter?
For a single prize, no. For multiple prizes drawn without replacement, earlier draws slightly affect later ones, which is why the multi-prize calculation is more involved. In practice the effect is small unless the number of prizes is a large share of the tickets.
Is what I enter stored?
No. Figures are processed in your browser and never transmitted or retained.
Related tools
References
- Gambling Commission — rules on raffles, lotteries and society lotteries
- GOV.UK — running a lottery or raffle for charity
Sources are checked at publication and can change — how I choose and check references.