Implied Probability Calculator
Turn American odds into the chance they imply. Add every side of the market to see how much vig the sportsbook has built in, and the chance of each outcome once it is taken out.
Published
What implied probability means
Odds are a price, and every price implies a chance: the win rate at which a bet at those odds breaks even. -150 implies 60%, +130 implies 43.48%. It is not the real chance of the outcome. Every line includes the sportsbook's vig, so the implied chances across a market add up to more than 100%.
Overround, hold and no-vig chances
The amount a market's implied chances add up to above 100% is the overround. The hold is the share of every dollar staked the sportsbook keeps if the money on each side balances: 1 − 1 ÷ the total book, always a little smaller. Divide each implied chance by the total book and you get the no-vig chances, which add up to 100% again. The no-vig calculator turns them back into fair odds, and the vig calculator says whether a market's margin is wide or sharp.
The formula
implied = 100 ÷ (A + 100) (plus odds)
total book = implied₁ + … + impliedₙ
no-vigᵢ = impliedᵢ ÷ total book
Worked example
A moneyline at -150 and +130. The odds imply 60% (150 ÷ 250) and 43.48% (100 ÷ 230), which add up to 103.48%: an overround of 3.48% and a hold of 3.36%. Divide each by the 103.48% total and the no-vig chances are 57.98% and 42.02%, fair odds of -138 and +138.
A chance worth holding the price against
HaterPicks projects player-prop lines and grades every projection win or lose against the result, so there is a number to compare the implied chance with. Free account · no card.
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FAQ
How do you calculate implied probability from American odds?
For a minus price, divide the odds by the odds plus 100, ignoring the sign: -150 is 150 ÷ 250 = 60%. For a plus price, divide 100 by the odds plus 100: +130 is 100 ÷ 230 = 43.48%. It is the win rate at which a bet at those odds breaks even.
Why do the implied probabilities add up to more than 100%?
Because every price includes the sportsbook’s vig. A fair coin-flip line would be +100 on both sides, 50% each. Sportsbooks price it at -110 on both sides instead, 52.38% each, and the extra 4.76% is the overround.
What is the difference between the overround and the hold?
The overround is how far the total book is above 100%: two -110 sides make 104.76%, a 4.76% overround. The hold is the share of all money wagered the sportsbook keeps on a balanced book: 4.55% on the same line. Both describe the same vig; the hold is the smaller number.
How do I use implied probability?
Compare it with your own estimate of the chance. If you make a team 45% to win and the odds imply 40%, the odds are longer than they should be; at 35%, they are too short. The EV calculator turns that difference into dollars.