Enter your stake, honest win probability, and the American odds. The calculator returns expected value in dollars, EV as a percentage of stake, edge over the market, and the breakeven probability you need to be a long-run winner at this price.
Expected value is the dollar amount you'd average per bet if you placed the same bet, at the same price, with the same win probability, an infinite number of times. The formula is straightforward: EV = (probability of winning × amount won) − (probability of losing × amount lost).
A positive EV means the bet is profitable in the long run. A negative EV means it isn't — even if it wins individually, the math says you'd lose money making the same bet repeatedly. EV % expresses that dollar EV as a percentage of your stake, which makes it easy to compare bets of different sizes.
The edge (in percentage points) is the gap between your estimate and the market's implied probability. If the market prices a bet at 47.6% implied probability (-110) and your model says 53%, your edge is +5.4 percentage points.
The breakeven win rate is the implied probability at the offered odds — the rate you have to win at, long-run, just to break even after the book's hold. Your true win probability must beat the breakeven by a meaningful margin to overcome variance and survive a long losing streak. Sharp bettors usually want at least 2-3 points of edge before pulling the trigger.
EV is the foundation of every legitimate sports-betting strategy. Read more on finding mispriced odds →