Odds converter

The three formats

Decimal odds are the total return on a one-unit stake, stake included: 2.50 returns 2.50 for every 1 staked, a profit of 1.50. They are the standard in Europe, Australia and on exchanges, and they are what every calculation on this site uses, because multiplying a probability by a decimal price gives the expected return directly.

Fractional odds are the profit relative to the stake: 6/4 means a profit of 6 for every 4 staked, so the return on 4 is 10. They are the traditional format in Britain and Ireland. Prices shorter than evens have the larger number second (4/6).

American odds are quoted relative to 100. A positive line is the profit on a 100 stake (+150 wins 150); a negative line is the stake needed to win 100 (−200 needs 200 to win 100). Evens is +100 or −100.

What the implied probability tells you

Every price implies a probability: one divided by the decimal price. That figure includes the bookmaker’s margin, so in a three-way market the three implied probabilities add up to something like 105%, not 100%. The bookmaker margin calculator strips that out to show the fair probabilities.

Comparing the implied probability to your own estimate of the chance is the whole of value betting. If you think an outcome is likelier than the price implies, the price is long for you; the expected value calculator puts a number on the gap.

Questions

How do I convert fractional odds to decimal?

Divide the first number by the second and add one. 6/4 is 6 ÷ 4 + 1 = 2.50. 10/11 is 10 ÷ 11 + 1 = 1.91.

How do I convert American odds to decimal?

A positive line (+150) is the line ÷ 100 + 1, so +150 is 2.50. A negative line (−200) is 100 ÷ the line + 1, so −200 is 1.50.

What is the probability implied by a price?

One divided by the decimal price. 2.50 implies 40%. Because the bookmaker builds in a margin, the implied probabilities of every outcome in a market add up to more than 100%.

Why does 1.91 show as 10/11 rather than 91/100?

Bookmakers quote fractional prices from a traditional set and round the decimal equivalent to two places. 10/11 is 1.909, shown as 1.91. The converter gives the simplest fraction that reproduces the decimal price to two places, which is the one you will see on a coupon.

The same numbers on real fixtures

• Where our probabilities disagree most with the prices
• Today’s fixtures with a probability on each prediction
• How the site turns probabilities into fair prices