Odds Calculator
Convert odds to implied probability, in any format
Frequently Asked Questions
Probability = odds for ÷ (odds for + odds against). For example, "1 to 4" odds mean 1 ÷ (1+4) = 20% probability.
Probability = 1 ÷ decimal odds. Decimal odds of 2.50 imply a 1/2.50 = 40% probability.
Positive odds (e.g. +150) show profit per $100 staked on an underdog; probability = 100 ÷ (odds + 100). Negative odds (e.g. -200) show the stake needed to win $100 on a favorite; probability = |odds| ÷ (|odds| + 100).
Bookmaker odds include a built-in margin (the "vig" or "overround"), so the implied probabilities of all outcomes in a market typically sum to slightly more than 100%.