Expected Value Calculator

How to use it

1. 1 Choose an odds format and type the odds you can bet at.
2. 2 Enter your own estimate of the chance the bet wins, as a percentage.
3. 3 Enter your stake, then read the EV in dollars, the EV as a percent of stake, and the break-even probability.

What expected value means

EV is a long-run average, not a prediction for one bet. A bet with +$12.50 EV can still lose on any single try, but if your probability is right, placing many such bets would average out to $12.50 of profit each.

EV is only as accurate as your win probability. The calculator cannot know the true chance, so the result is only a reliable guide if your estimate is. A common starting point is a no-vig fair price from a sharp market.

How it is calculated

EV in dollars is your win probability times the profit if it wins, minus your loss probability times the stake. EV percent divides that by the stake. The break-even probability is one divided by the decimal odds: the win rate you need just to cover the price.

This calculator treats a bet as win or lose. It does not model a push, where the stake is returned, which can happen on whole-number spreads and totals.

Worked example

You can bet +150 and you estimate the chance of winning at 45%. With a $100 stake, a win profits $150 and a loss costs $100.

EV is 0.45 x $150 minus 0.55 x $100, which is $12.50, or 12.50% of the stake. The break-even probability at +150 is 40.00%, so your estimate is 5.00 points above it (shown as +5.00 pts).

The formula

Frequently asked questions