Expected value (EV) calculator

Expected value (EV) is the average amount you would win or lose per bet if you placed the same bet many times. A positive EV (+EV) bet is one where the odds offered are higher than the true fair odds, giving you a mathematical edge over the bookmaker. Long-term profitable bettors focus on finding and placing +EV bets and let the sample size do the rest.

The formula is: EV = Stake × (Probability × (Odds − 1) − (1 − Probability))

For example, if you believe an outcome has a 52% chance of winning and the odds are 2.10 with a 10 unit stake: EV = 10 × (0.52 × 1.10 − 0.48) = 10 × 0.092 = 0.92 units expected profit per bet. The same bet placed 100 times is worth about 92 units.

Your own estimate. A model or a well-informed opinion, entered as a percentage. Useful for checking a single bet, but only as good as the estimate.

Fair odds. If you already know the no-margin price of the selection, the probability is simply 1 divided by those odds. The fair odds calculator derives this from any set of bookmaker odds.

Sharp book prices. The most practical method for most bettors: take both sides of a two-way market from the sharpest bookmaker you can see, remove the margin, and use the result as the true odds. Trackbet does exactly this for every bet you add, using the sharpest market's current and closing price.

Edge = Probability × Odds − 1. A 3% edge means you expect to profit 0.03 units per unit staked. The break-even win rate is 1 divided by the odds: at 2.10 you must win more than 47.6% of the time. Once a bet is +EV, the Kelly criterion tells you how much of your bankroll to risk, and the variance simulator shows how many bets it takes for that edge to show up in your results.