Implied probability calculator
Worked example
A price of -150 is 1.667 in decimal odds, so the implied probability is 1 / 1.667 = 60.0%. A price of +200 implies 33.3%. Those are different sides of different markets; the two sides of one market add up to more than 100% because of the book's margin.
How it works
Implied probability is the break-even win chance for a price: stake that price over many bets and you come out even only if the outcome happens at least that often. For a minus price it is the price divided by the price plus 100; for a plus price it is 100 divided by the price plus 100.
It is not a forecast. A book's prices include its margin, so the implied probabilities of both sides of a market sum to more than 100%. To take the margin out, use the no-vig calculator.
Frequently asked questions
How do I calculate implied probability from American odds?
For a minus price, divide the price (ignoring the minus sign) by itself plus 100, so -150 is 150 / 250 = 60%. For a plus price, divide 100 by the price plus 100, so +200 is 100 / 300 = 33.3%.
Is implied probability the real chance of winning?
No. It is the chance the price suggests, with the book's margin still inside it. The real chance is unknown, and two people can disagree about it.
Why do both sides of a bet add up to more than 100%?
The extra is the book's margin, often called the vig. A -110 and -110 market implies 52.4% on each side, so 104.8% in total.
Can I enter a prediction market price?
Yes. A contract priced at 40 cents implies 40%, so type 40 in the implied probability field to see the matching American and decimal odds.
Related
- Odds converter: American, decimal and implied probability
- No-vig (fair odds) calculator
- Expected value (EV) calculator
- All odds calculators
- Implied probability in the Glossary
- Prediction Market Prices vs Sportsbook Odds: How to Compare Them
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