Implied Probability Calculator — Odds to Win %
Every set of odds is a claim about how likely something is. This implied probability calculator turns any American, decimal, or fractional price into the win percentage it implies, and works the other way too — enter a probability to get the fair odds.
The formulas
implied probability = 1 / decimal odds negative American: |odds| / (|odds| + 100) positive American: 100 / (odds + 100) fair decimal odds = 1 / probability
Reference
+300 → 25.00% +150 → 40.00% +100 → 50.00% -110 → 52.38% -150 → 60.00% -200 → 66.67%
Implied vs. true probability
Implied probability is what the price needs, not what is true. It includes the sportsbook's margin, so it overstates every outcome slightly. Strip that out with the no-vig calculator, measure it with the vig calculator, or read the guide on how to read American odds.
FAQ
What is implied probability?
Implied probability is the chance of winning that a set of odds represents: 1 divided by the decimal odds. +150 implies 40%, -110 implies 52.38%, and -200 implies 66.67%.
How do I convert American odds to a percentage?
For negative odds, divide the odds (without the minus sign) by itself plus 100: 200 ÷ 300 = 66.67% at -200. For positive odds, divide 100 by the odds plus 100: 100 ÷ 250 = 40% at +150.
Why does implied probability add up to more than 100%?
Because the sportsbook builds in a margin. Two -110 prices imply 52.38% each, 104.76% in total. The extra is the vig; remove it with the no-vig calculator to get true fair probabilities.
How do I turn a probability into odds?
Fair decimal odds are 1 divided by the probability. A 60% chance is 1.667 decimal, or -150; a 25% chance is 4.00 decimal, or +300. Switch the tool to Probability → odds.