Implied Probability Calculator
An implied probability calculator converts a sportsbook price into the win rate needed to break even before considering market margin. American −110 corresponds to 52.38%, while +150 corresponds to 40%. In a complete market, the outcomes often sum above 100% because the bookmaker’s vig is still included.
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Implied probability is the break-even win rate baked into the odds. If the sportsbook offers -110, the implied probability is about 52.4%—you need to win that often just to break even. This calculator converts any American or decimal odds into implied probability in one click.
Use it to compare your estimated win chance to the market's price and spot +EV opportunities.
Implied Probability
Worked example: -110, +150 and decimal 1.91
For negative American odds, divide the absolute value by itself plus 100: -110 gives 110 ÷ 210 = 52.38%. For positive odds, divide 100 by the odds plus 100: +150 gives 100 ÷ 250 = 40.00%. For decimal odds, divide 1 by the price: 1.91 gives 52.36%, a touch below the 52.38% of the exact -110 value (1.909), which shows how much a rounded decimal display moves the answer.
Each result is a break-even rate. A bettor who wins 52.38% of bets at -110 ends level over time; one who wins 40% of bets at +150 also ends level. Win more often than the implied probability and the bet is profitable on average; win less and it loses.
Break-even win rates for common prices
Favorites: -105 needs 51.22%, -110 needs 52.38%, -115 needs 53.49%, -120 needs 54.55%, -150 needs 60.00%, -200 needs 66.67%, and -300 needs 75.00%. Even money, +100, needs exactly 50.00%.
Underdogs: +105 needs 48.78%, +120 needs 45.45%, +150 needs 40.00%, +200 needs 33.33%, +300 needs 25.00%, and +500 needs 16.67%. Over 100 bets at -110 you need about 52.38 wins to break even; at -120 that rises to about 54.55.
Why both sides add up to more than 100%
Convert both sides of a market and the total is over 100%. A -110/-110 spread sums to 104.76%; a -150/+130 moneyline sums to 103.48%. The excess is the sportsbook’s margin. The implied probability of each side therefore overstates the market’s real opinion of it. To estimate the fair probability, divide each side by the total, which is what the no-vig calculator does.
Comparing implied probability with your own estimate
The number becomes useful next to an estimate of your own. If you think a +150 underdog wins 45% of the time, that is 5 percentage points above its 40.00% break-even, worth about +$12.50 per $100 wagered. Rate it at 38% instead and the same bet is worth about -$5.00 per $100.
Edges are worth different amounts at different prices. A favorite at -150 that you rate at 62%, 2 points above its 60.00% break-even, is worth about +$3.33 per $100. A 2-point shortfall on the +150 underdog cost $5.00 per $100. Expected value turns these gaps into dollars, so pair this tool with an EV calculation before sizing a bet.
Implied probability questions
What is the implied probability of -110?
52.38%. That is 110 divided by 210, and it is the win rate a bettor needs at -110 to break even.
Is implied probability the chance my bet wins?
Not exactly. It includes the sportsbook’s margin, so it overstates the market’s fair estimate. Remove the vig to get a fair probability, then compare that with your own estimate.
How do I convert decimal odds to implied probability?
Divide 1 by the decimal odds. 2.50 is 40.00%, 1.50 is 66.67% and 3.00 is 33.33%.
What win rate do I need to profit at -110?
More than 52.38%. A 53-47 record of $100 bets at -110 finishes about $118 ahead.