This odds converter switches a price between decimal, fractional and American odds. It also shows the implied probability, which is the chance of winning that the price suggests.
So whichever format a bookmaker uses, you can read the price the same way.
Odds converter
The short version
- Decimal odds include your stake: 3.50 returns £3.50 for each £1.
- Fractional a/b becomes a/b + 1 in decimal.
- Implied probability = 1 ÷ decimal odds.
How to use the odds converter
Type a price into any one box: decimal, fractional or American. Then the odds converter fills in the other two formats and the implied %.
For American odds, use a plus sign for prices above evens, such as +250. Use a minus sign for favourites, such as −150.
Worked example
Worked example
Take a price of 5/2. In decimal, that is 5 ÷ 2 + 1 = 3.50. In American odds it is +250, because a £100 stake would win £250.
The implied chance is 1 ÷ 3.50 = 28.6%.
Now try a favourite at 4/6. That is 4 ÷ 6 + 1 = 1.67 in decimal, or −150 in American odds, because you stake £150 to win £100. The implied chance is 1 ÷ 1.67 = 60%.
What the result means
The implied % is the chance at which the price is fair. However, it is not the true chance. Bookmakers build in a margin, so the implied % of every outcome in a market adds up to more than 100%. Our guide to implied probability explains this in full.
If you think the real chance is higher than the implied %, the price may be value. Even so, that is only your estimate. To strip out the margin, use the fair odds calculator, and to compare prices with your own view, try the expected value calculator.
Why use an odds converter at all?
Many UK sites show fractions, while exchanges and most tools use decimals. Also, US sources quote American odds. An odds converter puts them all on one scale, so you can compare like with like. For background on the formats, see the Wikipedia article on odds.
Related guides and calculators
- Implied probability: what betting odds really say
- Fair odds and bookmaker margins
- All betting calculators
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