EV Calculator
Enter your win probability, odds and wager to see whether a bet is +EV — and what it's worth in the long run.
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What Is Expected Value in Sports Betting?
Expected value (EV) is what a bet is worth on average — the profit or loss you'd expect per wager if you could place the same bet thousands of times. It combines two things: how often the bet wins, and how much it pays when it does. The formula is simple: EV = (win probability × profit) − (loss probability × stake). A positive number means the odds are paying you more than the risk justifies.
How to Use the EV Calculator
- Enter your win probability — your best estimate of how often the bet wins.
- Enter the odds — the American odds your sportsbook is offering.
- Enter your wager — the calculator returns the bet's expected ROI and its expected value in dollars.
A quick example
Say you give a bet a 55% chance to win and a book offers -110. A $100 wager profits $90.91 when it wins. EV = 0.55 × $90.91 − 0.45 × $100 = +$5.00 — a +5% ROI. The same bet at 50% win probability would be −$4.55, which is exactly the sportsbook's built-in edge at -110.
Estimating win probability is the hard part — it's where the edge really lives. OddsShopper's paid tools run this exact computation across the whole board, using win probabilities computed from the live market across every major sportsbook. Pair this calculator with the hold calculator to see what you're paying in juice, and the arbitrage finder for risk-free spots.
EV Calculator FAQ
What is a +EV bet?
A positive expected value (+EV) bet is one where the odds pay more than the true chance of winning justifies. Any single bet can lose, but placing +EV bets over and over is the only mathematically sound way to profit from sports betting long-term.
How do I estimate my win probability?
The most reliable method is de-vigging the market: take the odds on both sides of a market, strip out the sportsbook’s margin, and the remaining implied probabilities are the market’s true estimate. Comparing one book’s price against that consensus is how professional bettors find +EV spots.
Is +EV betting actually profitable?
Over a large sample, yes — that is the definition of positive expected value. In the short run variance dominates: even a bettor placing only +EV wagers will have losing days and weeks. Sensible stake sizing relative to your bankroll is what lets the math play out.
What is a good EV percentage?
Most real +EV opportunities against the market consensus fall in the +1% to +6% range. Anything dramatically higher usually means the line is stale or the win probability estimate is wrong — treat double-digit EV with skepticism.