Kelly Criterion Calculator
Optimal bet sizing for +EV bets
Expected Value Calculator
Find out if a bet has positive expected value (+EV) and calculate your edge over the sportsbook.
Calculate Expected Value Free
$
%
Expected Value (EV)
+$12.50
Book's Implied Prob
40.00%
Your Edge
+5.00%
If You Win
+$150.00
If You Lose
-$100.00
✅ This is a +EV Bet!
Your estimated probability (45%) is higher than the book's implied probability (40%). Over time, this type of bet should be profitable.
How to Use This Calculator
1
Enter Your Bet Amount
How much you plan to wager on this bet.
2
Enter the Odds
The American odds offered by the sportsbook (e.g., +150 or -110).
3
Estimate Win Probability
Your honest assessment of how likely this bet is to win. This is the key input—be realistic!
4
Review Your Results
If EV is positive, you have an edge. If negative, the book has the edge.
Understanding Expected Value
📐 The EV Formula
EV = (Win Probability × Profit if Win) - (Loss Probability × Stake)
A positive EV means the bet is profitable long-term. Negative EV means you'll lose money over time.
What Is "Edge"?
Your edge is the difference between your estimated probability and the book's implied probability. If you think a team has a 50% chance to win, but the odds imply only 40%, you have a 10% edge.
⚠️ The Most Important Thing
EV calculations are only as good as your probability estimate. If you consistently overestimate your accuracy, you'll think you're finding +EV bets when you're actually losing money. Be brutally honest with yourself.
EV Quick Reference
| Odds | Implied % | Your Est. % | EV per $100 | Verdict |
|---|---|---|---|---|
| +200 | 33.3% | 40% | +$20.00 | ✅ +EV |
| -110 | 52.4% | 55% | +$4.55 | ✅ +EV |
| -150 | 60.0% | 55% | -$8.33 | ❌ -EV |
| +150 | 40.0% | 40% | $0.00 | ➖ Break-even |
💡 Pro Tip: Finding +EV Bets
Look for situations where sportsbooks have mispriced a line—often after news breaks (injuries, weather) or on less popular markets where books set lazier lines. Line shopping across multiple books also helps find better odds.
Learn More About +EV Betting
Check out our comprehensive guide to finding profitable bets.
EV Betting Guide →