Implied Probability in Betting
Every price carries a percentage inside it. Learning to read that percentage helps you see what a price is asking of you.
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What implied probability means
Implied probability is the chance of a win that a price needs in order for a bettor to break even. It is a way to read a price as a percentage instead of a number like -110 or +150.
The formulas
For minus odds, divide the number (without its sign) by itself plus 100. For plus odds, divide 100 by the number plus 100.
- -110: 110 / 210 = 52.4%
- -200: 200 / 300 = 66.7%
- +150: 100 / 250 = 40%
- +100: 100 / 200 = 50%
Why the two sides add to more than 100%
If both sides of a spread are -110, each side is 52.4%, and together they add to 104.8%. A fair coin flip would be 50% and 50%, adding to exactly 100%. The extra 4.8% is the margin the sportsbook builds into the prices.
A moneyline of -120 on one side and +100 on the other shows the same thing: 54.5% plus 50% is 104.5%. To estimate a fair price, divide each side by the total. For -110 and -110, 52.4 / 104.8 is 50%.
What it does and does not tell you
Implied probability tells you the win rate a price demands. At -110, a bettor needs to win more than 52.4% of the time to profit. It also helps compare prices, since 40% at +150 is a much lower bar than 52.4% at -110.
It does not say who will win. A price is the market's estimate after the margin, not a fact about the game, and any estimate can be wrong.
Bets can lose, and nobody should bet money they cannot afford to lose. Bettors must be 21 or older where betting is legal. If gambling is a problem for you or someone you know, call 1-800-GAMBLER.
Questions
Is implied probability the same as the true chance?
No. It includes the sportsbook's margin and reflects where bets have landed. It is a useful reference, not a forecast.
How do I convert +200 to a percentage?
Divide 100 by 300 (the number plus 100). That gives 33.3%.
Why does a favorite show a higher percentage?
A favorite is expected to win more often, so the price demands a higher win rate. -200 needs 66.7%, while +150 needs 40%.
More guides
For information and entertainment only. Bets can lose. 21+ only, and only where it is legal. If gambling is a problem, call 1-800-GAMBLER. See our responsible gaming page.