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Implied Probability Calculator

Convert American odds into implied probability — the win rate a price assumes. Enter both sides of a two-way market to also see the sportsbook's vig and the fair, no-juice probabilities.

Side A implied
60.00%
Side B implied
43.48%
Total (with vig)
103.48%
Sportsbook hold
3.48%
Devigged fair probabilities
Side A fair: 57.98%
Side B fair: 42.02%

For full fair-odds output (including the no-juice American price), use the fair odds calculator.

How implied probability works

Every betting line corresponds to a break-even win rate. A −110 favorite implies 52.38% (110 / 210). A +250 underdog implies 28.57% (100 / 350). On a two-way market with vig, both sides will sum to more than 100% — that excess is the sportsbook's hold. Strip it out and you get the fair probability that the market actually believes.

Worked example — moneyline with vig

  1. 1
    Side A: −150 → 60.00%
  2. 2
    Side B: +130 → 43.48%
  3. 3
    Total: 103.48%
    Sportsbook hold: 3.48%
  4. 4
    Side A fair: 60.00 / 103.48 = 57.98%
  5. 5
    Side B fair: 43.48 / 103.48 = 42.02%
The market's true read on Side A is closer to 58%, not the 60% the line implies. If you can find Side A priced at better than −138 (the fair American price), the bet is +EV. Drop it into the Slip Analyzer to grade it.

Frequently asked questions

What is implied probability in sports betting?+

Implied probability is the win rate the sportsbook's odds assume. A −200 line implies the bet must win 66.67% of the time to break even. It's the price expressed as a percentage instead of as odds.

How do you calculate implied probability from American odds?+

For negative odds: |odds| / (|odds| + 100). For positive odds: 100 / (odds + 100). Example: −150 → 150/250 = 60%. +200 → 100/300 = 33.33%.

Why don't both sides of a market add up to 100%?+

Because of the sportsbook's vig. If you sum the implied probabilities of both sides of a moneyline (say −110 / −110 → 52.4% + 52.4% = 104.8%), the extra 4.8% is the book's hold. The devig calculator removes that hold to find fair probabilities.

What's the difference between implied probability and fair probability?+

Implied probability includes the vig — it's the break-even rate at the book's price. Fair probability strips the vig — it's the true two-sided estimate of how often the bet wins. Use the fair odds calculator to convert one to the other.

How can I use implied probability to find +EV bets?+

Compare the implied probability of your sportsbook's price to your own estimate (or the devigged market consensus). If your estimated win rate is higher than the implied probability, the bet is +EV.