Odds converter
American, decimal, fractional and implied probability are four ways of writing exactly the same price. Type into any box and the other three follow.
Odds format converter
American, decimal, fractional and implied probability are four ways of writing the same price. Change any box and the other three follow.
Fractional odds come off a fixed ladder of denominators, so the fraction shown is the closest one a board would actually print rather than an exact ratio with a four digit denominator.
What the four formats actually say
American odds are written around a 100 unit stake. A negative number is how much you have to risk to win 100, so -110 means risking 110 to win 100. A positive number is how much you win from a 100 stake, so +150 means a 100 stake returns 150 in winnings plus your stake back.
Decimal odds are the total return per unit staked, stake included. 1.91 means a 10 stake returns 19.10 in total. Exchanges and most of the world outside the United States quote this way, and it is the easiest format to multiply, which is why the arithmetic behind most betting tools runs on it internally.
Fractional odds are a ratio of winnings to stake, so 10/11 means stake 11 to win 10. They come off a fixed ladder of denominators, which is why a converted fraction is the closest one a real board would print rather than an exact ratio with a four digit bottom half.
Implied probability is the same price expressed as a percentage chance. It is the most useful of the four for comparing anything, because it turns two prices written in different alphabets into two numbers you can subtract.
Questions people ask about this one
Why do the implied chances on both sides add up to more than 100%?
Because the sportsbook's margin is built into both prices. That overround is the vig, and it is the difference between the price you are offered and a fair price. Strip it out with the no vig calculator.
Is -110 the same as 1.91?
Yes. They are the same price written two ways, and both imply a 52.38% chance. That is the standard price on a two way market at most American sportsbooks.
Which format should I work in?
Whichever your book shows, for placing. Decimal for anything you are calculating by hand, because it multiplies cleanly and American does not.
The other calculators
Expected value, parlay odds, Kelly staking, prediction market prices and the bonus bet converter are all on the main calculators page, free and with no account. How these numbers feed the rest of the product is set out in the methodology.