AMERICAN ODDS CALCULATOR
Convert two American moneyline prices into implied probabilities and see how the combined prices include a bookmaker margin. Educational only, no sportsbook account needed.
Convert two-way moneyline odds
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For two-outcome markets only. A three-way soccer market, a draw price or a special prop requires a different calculation. These are not win predictions or promised fair prices.
How does American odds probability work?
For positive American odds +A, the implied probability is 100 ÷ (A + 100). For negative odds -A, it is A ÷ (A + 100), using the absolute value A. For example, +150 converts to 40% while -150 converts to 60%. These percentages describe the quoted prices, not the actual outcomes of a game.
Why do two moneylines add to more than 100%?
Sportsbooks commonly quote both sides with a built-in margin, also called overround or vig. Two prices of -110 and -110 imply about 52.38% each. Added together, that is roughly 104.76%; the excess 4.76 percentage points is the overround, not a guaranteed profit or a probability that either team wins.
What does no-vig normalization mean?
A common approximation divides each quoted implied probability by their combined total so they add to 100%. It proportionally removes the overround but does not make the result a calibrated forecast. This calculator cannot determine a team’s true probability or whether a price is favorable.
Should I use these results for a bet?
Use the output only to understand quoted prices. Current odds, lineup availability, settlement terms and responsible-play limits all matter. No number guarantees a result. For help with gambling in the U.S., call or text 1-800-GAMBLER.