EV Calculator for Sports Betting
Instantly calculate expected value, edge, and optimal bet size for any wager
Enter Your Bet Details
Your Odds (American)
Positive for underdogs (+150), negative for favorites (-110)
Fair Win Probability: 55%
Bet Size ($)
EV Formula
Expected Value
+5.00% EV
This bet has positive expected value
52.4%
+2.6%
+0.050
+5.00
5.5% of bankroll
Over 100 bets at $100, your expected profit is $500.00.
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How To Use This EV Calculator
Enter the odds from your sportsbook in American format (e.g., -110 for favorites, +150 for underdogs).
Set your fair win probability — your best estimate of the true chance this bet wins. Use the slider or type a value. This is the key input: your edge comes from estimating probability more accurately than the sportsbook.
Enter your bet size to see expected profit in dollar terms.
Read the results — all outputs update instantly. Look for positive EV% and a green gauge.
Example: Is -110 at 55% a Good Bet?
At -110 odds, the implied probability is 52.4%. If you believe the true probability is 55%, your edge is 2.6% and your EV is +4.5%. That's a profitable bet over the long run.
The Kelly Criterion would suggest risking about 5% of your bankroll on this bet. Most sharp bettors use fractional Kelly (25-50%) for lower volatility.
Frequently Asked Questions
What is expected value in sports betting?
Expected value (EV) measures the average profit or loss you can expect per bet over the long run. A +EV bet means the odds are in your favor relative to the true probability of the outcome. Professional bettors focus exclusively on finding +EV opportunities because they lead to long-term profitability, even if individual bets lose.
How do you calculate EV for a bet?
EV is calculated using the formula: EV = (Fair Probability x Payout) - (1 - Fair Probability) x Stake. For American odds, payout equals odds/100 for positive odds or 100/|odds| for negative odds. Enter your odds and estimated fair win probability into the calculator above to see your EV instantly.
What is a good EV percentage?
Any positive EV percentage means the bet is theoretically profitable long-term. Professional bettors typically target bets with 3%+ EV. Bets with 5-10%+ EV are considered excellent opportunities but are rarer. Even small edges of 1-2% compound significantly over hundreds of bets.
What is the Kelly Criterion in sports betting?
The Kelly Criterion is a mathematical formula that calculates the optimal percentage of your bankroll to wager on a bet based on your edge. It maximizes long-term bankroll growth while managing risk. The formula is: Kelly % = ((Fair Prob x (Payout + 1)) - 1) / Payout. Most bettors use "fractional Kelly" (25-50% of full Kelly) to reduce volatility.
What is implied probability?
Implied probability is the win percentage that the sportsbook odds suggest. For -110 odds, the implied probability is 52.4%. If your estimated fair probability is higher than the implied probability, the bet has positive expected value. The difference between your fair probability and the implied probability is your "edge."
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