Expected Value (EV) Calculator
An expected value calculator combines the offered odds with your estimated win probability to show average profit or loss per bet over repeated opportunities. Positive EV means your probability estimate beats the price’s break-even threshold. It does not mean the next wager will win, and inaccurate probability inputs produce misleading results.
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Expected Value (EV) is the average profit or loss you should expect over the long run. Positive EV suggests a bet is worth considering; negative EV suggests you’re paying too much for the price.
This calculator shows EV (in dollars), EV%, and the break-even win probability implied by the odds.
Expected Value Calculator
How EV Is Calculated
EV = (win probability × profit if you win) − (loss probability × amount staked). Profit if you win comes from the odds; break-even probability is 1 ÷ decimal odds. A 55% estimate at −110 (52.38% break-even) clears that bar for a +EV bet — see the worked math in Understanding Expected Value (EV) in Sports Betting. Here is the same price on the other side of that line.
-EV example: 48% win probability at -110
0.48 × $90.91 profit − 0.52 × $100.00 staked = -$8.36 EV (-8.36%). A 48% estimate falls short of the 52.38% break-even, so this is a −EV bet even though the price never changed.
Once you have a positive number, what edge actually means covers why a genuine edge still isn't guaranteed profit.
Worked example: EV on a -110 bet at 55% win probability
Expected value combines an estimated win probability with the payout on offer. At -110, a $100 stake wins $90.91 profit (100 ÷ 110 × 100). Estimate a 55% chance of winning and EV = (0.55 × $90.91) − (0.45 × $100) = $50.00 − $45.00 = $5.00 per $100 wagered, or +5.00% EV.
Drop that estimate to the market's own implied probability — 52.38% at -110 — and EV collapses to (0.5238 × $90.91) − (0.4762 × $100) = $47.62 − $47.62 = $0.00. That is not a coincidence: the market's own implied probability is by definition the break-even point, so any edge above +0.00% EV comes entirely from believing the true probability is higher than what the price implies.
A three-percentage-point gap between a 55% estimate and the market's 52.38% implied probability is enough to swing this bet from break-even to +5% EV — which is exactly why small errors in a probability estimate matter so much more here than in a simple payout calculation.
When EV alone isn't enough
A positive EV calculation is only as good as the probability fed into it. If that estimate comes from a gut feeling rather than a calibrated model or a defensible no-vig market read, a large EV number can be confidently wrong rather than genuinely profitable.
EV also says nothing about variance. Two bets can carry the same +5% EV while one has a 90% win probability and the other a 10% win probability at much longer odds; the long-shot bet needs a far larger sample before its results look anything like its theoretical average. Pair an EV estimate with bankroll management — flat units or fractional Kelly — so a string of losses on a genuinely +EV bet does not end the strategy before the long-run average has a chance to show up.
See how this is derived
EV calculator questions
What does positive EV mean?
It means the wager has a positive average projected return if your probability estimate is accurate and similar opportunities repeat.
Does +EV guarantee a winning bet?
No. A positive-EV wager can lose; EV describes a long-run average, not one outcome.
Where should win probability come from?
Use a calibrated model or a defensible no-vig market estimate, then account for uncertainty rather than guessing.
How is EV calculated?
Multiply your estimated win probability by the profit on a win, then subtract your loss probability times the amount staked: EV = (p(win) × profit) − (p(lose) × stake). A positive result is a +EV bet at your stated probability; a negative result is −EV.
What is an EV calculator used for in sports betting?
It converts offered odds and your win-probability estimate into a dollar EV and EV%, so you can compare wagers at different prices on the same footing instead of judging a bet by its odds alone.