Expected value (+EV) betting calculator
Enter the odds a book offers and your estimate of the fair odds. The calculator shows the bet's expected value: how much you'd make or lose per dollar on average over many bets like it, plus a suggested stake.
The expected value formula
EV = fair chance × decimal odds − 1
A bet with positive EV pays more than its chance of winning is worth. One bet can still lose; the edge shows over many.
Worked example
A book offers +150 (decimal 2.50). Your fair odds are +130 (decimal 2.30), a fair chance of 1 / 2.30 = 43.48%.
EV = 0.4348 × 2.50 − 1 = +8.70%, about $8.70 per $100 staked on average.
How much to bet
The Kelly criterion sizes a bet by its edge: (chance × odds − 1) / (odds − 1). Here that's 8.70% / 1.5 = 5.80% of your bankroll. Full Kelly swings hard when your estimate is off, so most bettors use a fraction; a quarter Kelly is 1.45%, or $14.49 on a $1,000 bankroll. This calculator never suggests more than 5%. See the Kelly calculator for more.
Where the fair odds come from
EV is only as good as your fair odds. Some bettors build a model; others take both sides' odds in a market they trust and strip out the book's cut with the no-vig calculator. Converge shows its own estimate beside every price on the board, and tracks every pick until the game starts.
Questions
What does +EV mean in sports betting?
+EV (positive expected value) means a bet pays more than its chance of winning is worth, so it makes money on average over many similar bets.
How do you calculate EV on a bet?
Multiply your estimated chance of winning by the decimal odds and subtract 1. A result above zero is +EV.
What is a good EV percentage?
Most real +EV bets are small, around 1% to 5%. Edges far above that are often stale prices or errors that a book may correct or void, so check them before betting.
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Updated 2026-10-26