Expected Value (EV) Calculator
Calculate the long-term expected profit or loss of any bet to make smarter wagering decisions.
What Is Expected Value in Betting?
Expected Value (EV) is the most important concept in professional sports betting. It measures the average amount you expect to win or lose per dollar wagered over the long run. A positive expected value (+EV) bet means you will profit over time; a negative expected value (-EV) bet means the house has the edge.
The formula is: EV = (Probability of Winning × Profit if Win) − (Probability of Losing × Stake Lost). If you flip a fair coin and someone offers +120 odds (instead of the fair +100), the EV is positive. You should take that bet every time, because even though you lose half the time, your wins more than compensate.
Every successful sports bettor — from casual sharps to professional syndicates — focuses on consistently finding and betting +EV opportunities. The concept applies universally across all sports, bet types, and markets.
How the EV Calculator Works
Enter the odds offered by the sportsbook and your estimated true probability of the outcome. The calculator computes: the expected value per dollar wagered, the expected ROI percentage, and whether the bet is +EV or -EV.
It also shows the breakeven probability — the win rate you'd need at those odds to break even. If you believe the true probability is higher than the breakeven, the bet has positive expected value.
For advanced users, the calculator supports comparing multiple bets side-by-side, helping you allocate your bankroll to the highest-EV opportunities. This is the foundation of any profitable betting strategy.
Finding +EV Bets
There are several ways to identify +EV betting opportunities:
Opening Line Value (OLV): Odds at market open often contain less information than closing lines. Betting early on lines that will move in your direction captures value.
Closing Line Value (CLV): If you consistently beat the closing line, you are a +EV bettor by definition. Track your CLV over time.
Promotions and Boosts: Sportsbook promotions (profit boosts, odds boosts, insurance) can turn -EV bets into +EV opportunities. Always calculate the actual EV of boosted odds.
Your Own Models: Building a model that estimates true probabilities better than the market is the gold standard. Even a 2-3% edge, applied consistently, generates significant long-term profit.
Worked Example: Is This NFL Bet +EV?
A sportsbook offers the Kansas City Chiefs at +140 to win their game. Your model estimates the Chiefs have a 45% chance of winning.
- Offered odds: +140 (decimal: 2.40)
- Your estimated probability: 45% (0.45)
- Breakeven probability at +140: 1 / 2.40 = 41.67%
- Since 45% > 41.67%, this is a +EV bet
- EV per $1 wagered: (0.45 × $1.40) − (0.55 × $1.00) = $0.63 − $0.55 = +$0.08
- Expected ROI: +8.0%
- On a $100 bet, you expect to profit $8 on average over many similar bets
This bet has a positive expected value of +8.0%. While you will lose 55% of the time, the higher payout when you win more than compensates. Over 100 such bets at $100 each, you expect approximately $800 in profit.
Frequently Asked Questions
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