Expected Value (EV) Calculator for Sports Bets
Expected value compares your own estimate of how often a bet wins with what the price pays. Enter your probability and the odds to see the average result per $100.
If 55.0% is right, a $100.00 bet at -110 averages +$5.00 per bet over many bets. The price pays more than your number says it should. Any one bet still wins or loses.
How expected value works
EV = (your win probability × profit if it wins) - (your loss probability × stake). With a 55% estimate at -110 on $100, a win profits $90.91: 0.55 × $90.91 - 0.45 × $100 = +$5.00 per bet on average.
Edge is your probability minus the price's implied probability. -110 implies 52.4%, so a 55% estimate is a 2.6-point edge. Fair odds are the price with no margin at your probability; any price better than that is positive EV by your numbers.
EV is only as good as the probability you put in. Hit rates are one input: how often a player cleared a line in their last 10 games is history, not a forecast, so treat it as a starting point for your estimate.
Learn the math
Questions
How do you calculate expected value on a bet?
EV = (your win probability × profit if it wins) − (loss probability × stake). At -110 with a 55% estimate on $100: 0.55 × $90.91 − 0.45 × $100 = +$5.00.
What does positive EV mean?
It means that if your probability estimate is right, the price pays more than the risk over many bets. EV is an average over the long run, not the result of the next bet, and it is only as good as your estimate.
What are fair odds?
The price with no margin at your probability: 1 divided by your probability, in decimal. A 55% estimate is 1.82 in decimal, about -122. Any price better than that is positive EV by your numbers.
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