Odds Converter

What this tool does

Sportsbooks don't all quote odds the same way. American books use numbers like -110 or +150. Decimal odds (common outside the US, and on most exchanges) show your total return per dollar staked, like 1.91 or 2.50. Fractional odds, the traditional UK format, show it as a ratio like 10/11. This tool converts freely between all three so you can compare a line quoted one way against a line quoted another without doing the math by hand.

How to use it

Enter a number into whichever field matches the odds you already have. For American, include the sign (-110 or +150). For decimal, use a number above 1.00 (like 1.91). For fractional, enter it as num/den (like 10/11). The other two fields and the probability update automatically as you type.

Why implied probability matters

Every price a sportsbook posts implies a probability of that outcome happening — that's literally what "odds" means. -110 implies about a 52.4% chance; +150 implies about 40%. Seeing that percentage next to the raw number is usually more useful than the odds format itself, since it's the one thing that's directly comparable across American, decimal, and fractional quotes. Note this is the market's implied probability before removing the sportsbook's built-in margin — for the "true," de-vigged probability between two sides of the same market, see the De-Vig Calculator.