Expected Value (EV) Calculator

Find positive expected value bets. Input the odds and your win probability estimate to see if a bet has mathematical edge.

Implied probability: 40.0%

-EV BET
0.00 (0.00%)
Expected value per $100 bet
Your Est. Win %
40%
Book Implied %
40.0%
Edge
0.0%
Profit if Win
$150.00
This bet has negative expected value of $0.00 per bet. Either find better odds or re-assess your win probability estimate.
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How to Use Our EV Calculator

Our EV calculator tells you whether a bet has a mathematical edge over the sportsbook. Enter the odds and your estimated win probability — the calculator instantly shows if the bet is +EV or -EV and by how much.

1
Enter the sportsbook's odds
Type in the American odds offered by the sportsbook — e.g., +150 for an underdog, -110 for a standard spread, +330 for a big underdog moneyline.
2
Enter your estimated win probability
This is your own assessment of how likely the team is to win — expressed as a percentage. For example, if you think a team has a 45% chance of winning, enter 45.
3
Enter your stake
How much you plan to bet. The EV calculator shows absolute expected value in dollars (not just percentages), so you can see your real expected profit per bet.
4
Read the EV result
Positive EV (+$X) means your edge over the book — you expect to profit that amount per bet on average over time. Negative EV means the bet loses money long-term. Only bet +EV situations.

EV Calculator Examples

+EV Example
Odds: +150
Win%: 45%
Stake: $100
EV: +$12.50

Book implies 40% win prob. Your model says 45%. That 5% edge = $12.50 expected profit per $100 bet.

-EV Example
Odds: -110
Win%: 48%
Stake: $100
EV: −$3.27

Book implies 52.4% win prob. You estimate 48%. You're below the break-even line — skip this bet.

How to Find +EV Bets

Finding +EV bets requires having a more accurate win probability estimate than the sportsbook. Here are the methods sharp bettors use:

  • Line Shopping: Compare the same game across 4–5 sportsbooks. If FanDuel offers +115 and DraftKings offers +100 on the same side, FanDuel is +EV relative to the consensus.
  • No-vig Fair Odds: Remove the vig from both sides of a market to get the true implied probability. If the no-vig line is -105 and a book offers +100, that's +EV.
  • Sharp Line Movement: When a line moves from -3 to -4.5, it usually means sharp money landed on the favorite. Following sharp moves is a proven +EV strategy.
  • Statistical Models: Build or use existing win probability models based on team performance, pace, injuries, and matchup data. If your model consistently diverges from the market line, exploit the difference.

Kelly Criterion — How Much to Bet on +EV Plays

Once you find a +EV bet, the Kelly Criterion tells you the optimal stake size to maximize bankroll growth. The formula:

Kelly % = (Win Prob × Decimal Odds − 1) ÷ (Decimal Odds − 1)
Example: +150 odds (2.50 decimal), 45% win prob → (0.45 × 2.50 − 1) ÷ (2.50 − 1) = 0.125/1.5 = 8.3% of bankroll

Most professional bettors use Half Kelly (4.15% in the above example) to reduce variance. Never bet more than the full Kelly amount — it maximizes long-run growth but the swings can be brutal. Use the EV calculator to confirm you have edge before sizing any bet.

Frequently Asked Questions

Expected Value (EV) measures the average profit or loss you'd expect per bet over the long run. A +EV bet means you have a mathematical edge over the sportsbook — your estimated win probability is higher than the book's implied probability. -EV bets have a negative expected long-term return. Sharp bettors focus exclusively on +EV bets.

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