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Odds converter

Convert any price between fractional, decimal and American in one place, and see the implied probability it assumes. Type a price in any format and the rest update instantly.

Odds converter
Auto-detect fractional, decimal, American and EVS.
Detected: Fractional
Fractional
5/2
Decimal
3.50
American
+250
Implied probability 28.57%
The break-even win rate this price assumes.

How to convert betting odds

Fractional, decimal and American odds are just three ways of writing the same price. Type any of them into the converter above and it reads the format automatically, shows the other two, and works out the implied probability.

Worked example: 5/2 = 3.50 decimal = +250 American, and the implied probability is 100 ÷ 3.50 = 28.6%.

Decimal odds

The total returned per £1 staked, stake included — 3.50 means £3.50 back for every £1, so £2.50 profit. Easiest for comparing prices and working out returns, which is why exchanges and most of Europe use it.

Fractional odds

Profit relative to stake — 5/2 means £5 profit for every £2 staked. Traditional in UK and Irish horse racing. "Evens" (EVS) is 1/1, i.e. 2.00 decimal.

American (moneyline) odds

A positive price (+250) is the profit on a 100 stake; a negative price (−200) is the stake needed to win 100. Standard across US sportsbooks.

Implied probability

Divide 100 by the decimal odds to get the win chance the price assumes: 100 ÷ 3.50 = 28.6%. That's your break-even strike rate — beat it consistently and you're a long-term winner.

Frequently asked questions

How do I convert fractional odds to decimal?+
Divide the fraction and add 1. So 5/2 = 2.5, then + 1 = 3.50 in decimal. To go the other way, subtract 1 and write it as a fraction: 3.50 − 1 = 2.5 = 5/2.
What are decimal, fractional and American odds?+
Three ways of writing the same price. Decimal (3.50) is the total returned per £1 staked, stake included. Fractional (5/2) is profit-to-stake. American shows the profit on a 100 stake for positive prices (+250) or the stake needed to win 100 for negative ones (−200).
What is implied probability?+
The win chance a price assumes, before the bookmaker's margin. Divide 100 by the decimal odds: 100 ÷ 3.50 = 28.6%. It's the break-even strike rate you'd need for the bet to be worth taking.
Which odds format should I use?+
Whichever you find clearest — they're identical prices. Decimal is easiest for comparing bookmakers and working out returns; fractional is traditional in UK and Irish racing; American is standard in the US.
Is the odds converter free?+
Yes — completely free and no signup. If you'd like Reko to track your bets and closing-line value automatically, you can create a free account.

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