Odds Converter
Fractional, decimal, American and implied probability, instantly.
Accepts fractional (5/2, 100/30, EVS), decimal (3.5) and American (+250, -200).
Reading the three formats
Fractional odds (5/2) are profit relative to stake: £2 staked wins £5. Decimal odds (3.50) are the total return per £1 including your stake. American odds show profit on $100 (+250) or the stake needed to win $100 (−200). Same price, three notations — decimal is the one the maths prefers, which is why professional bettors work in decimals.
The implied probability is the price expressed as a chance: 100 ÷ decimal odds. A 5/2 shot (3.50) implies 28.57%. Comparing that implied chance to your own estimate of the true chance is the entire basis of value betting — and note that a full market's implied probabilities sum to more than 100%, the excess being the bookmaker's margin.
FAQ
Why does 1/2 mean odds-on?
Fractional odds below 1/1 (evens) mean the profit is smaller than the stake: 1/2 wins £1 for every £2 staked — a 66.7% implied chance.
What's EVS?
Evens: 1/1 fractional, 2.00 decimal, +100 American, 50% implied.
Why do bookmakers still use fractions?
Tradition, mostly UK and Irish. Exchanges and most of the world use decimals; every vibeodds EV calculation runs on decimals underneath.