EV Calculator
Your fair probability plus the book’s price — expected value and expected profit per bet, instantly.
Every $10 bet at this price is worth +$0.50 on average — the edge is yours.
Worked example
Say you rate a pitcher’s strikeout over at 55% and the book hangs −110, which implies 52.4%. The EV is 0.55 × (100/110) − 0.45 = +5.0% — on a $10 stake that’s +$0.50 of expected profit every time you make that bet. Flip the fair probability to 50% and the same price is −4.5%: the bet didn’t change, the price did. That gap between your fair number and the implied number is the entire game.
FAQ
What is expected value (EV) in sports betting?
Expected value is the average profit or loss per bet if you could place the same bet thousands of times. It compares your estimated win probability (the fair probability) to the price the book is offering. Positive EV (+EV) means the price is in your favor over the long run; negative EV means the book’s margin is beating you.
How do I come up with a fair probability?
A fair probability is your honest estimate of how often the bet wins, before the book’s margin. Common approaches: devig a sharp book’s two-sided line (see our devig calculator), average several sharp books, or build your own projection from stats. The number you enter here should not include the vig.
Why does −110 need a 52.4% fair probability to break even?
At −110 you risk $110 to win $100, so the breakeven win rate is 110 / 210 = 52.38%. Any fair probability above that is +EV at −110; anything below it loses money on average even if you win often.
Does a +EV bet always win?
No. EV is a long-run average, not a promise. A bet with a 55% fair probability still loses 45% of the time. What +EV means is that repeating bets like it grows a bankroll over hundreds of wagers — variance dominates any single outcome.
What EV% is worth betting?
That depends on your bankroll discipline, but most serious bettors look for at least +2–3% to cover estimation error in their fair probability. A tiny +0.5% edge is easily wiped out if your fair number is slightly off.
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