Odds to Probability Converter
Convert between odds and probability. Enter odds like 3:1 to get the percent chance, or a percentage to get the implied odds.
Last reviewed by the Radiatus Cloud team
Convert betting-style odds to a probability percentage and back.
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Convert between odds and probability
Odds and probability are two ways of expressing the same chance. Probability states the fraction of times an event is expected to happen, usually as a percentage. Odds compare the number of favourable outcomes to unfavourable ones, written like three to one. This converter translates between them in both directions. Odds of a to b in favour correspond to a probability of a divided by a plus b, and a probability can be turned back into whole-number odds and decimal odds.
Decimal odds, common in betting, are also shown: they equal one divided by the probability and represent the total return per unit staked.
Why convert odds and probability
Bettors convert the odds offered by a bookmaker into an implied probability to judge whether a bet offers value. Students and analysts move between the two forms because probability is easier to combine mathematically while odds are the traditional way chances are quoted. Risk and gaming professionals use both daily.
The tool uses the common convention that odds "a to b in favour" mean the event wins a times for every b times it loses. Probabilities must lie strictly between zero and one hundred percent, since certainty and impossibility do not correspond to finite odds. All calculation runs locally in your browser.
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Frequently Asked Questions
How do odds relate to probability?
Odds of a to b in favour give a probability of a divided by a plus b. For example three to one in favour is three divided by four, or seventy-five percent.
What are decimal odds?
Decimal odds equal one divided by the probability. They show the total payout per unit staked, including the return of your stake.
What does "in favour" mean?
Odds in favour list favourable outcomes first, so three to one means three wins for every one loss. Odds against reverse the order.
Why must probability be between 0 and 100?
A probability of zero or one hundred percent represents impossibility or certainty, which cannot be written as finite, meaningful odds.
Can I convert a percentage to odds?
Yes. Enter the probability percentage and the tool returns simplified whole-number odds in favour and the equivalent decimal odds.
Privacy & Security
Everything runs in your browser; nothing is uploaded.
How to Use
Enter odds as two numbers, or a probability percentage, and convert.
Disclaimer: This tool is provided "as is" without warranty of any kind. Results are for educational and utility purposes.
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