Expected Value (EV)
generalThe average amount a bettor can expect to win or lose per bet if the same bet were placed many times. Positive EV (+EV) bets are profitable long-term.
Key Takeaways
- 1EV is the average expected outcome over many repetitions
- 2+EV bets are profitable long-term, -EV bets are not
- 3Every casino game has negative EV for the player
- 4Individual results don't determine if a bet was good or bad
What is Expected Value?
Expected Value (EV) is the most important concept in all of gambling. It represents the average outcome of a bet if it were repeated an infinite number of times.
The Formula
EV = (Probability of Winning × Amount Won) - (Probability of Losing × Amount Lost)
Example
A coin flip bet paying +110 (bet $100 to win $110):
- EV = (0.50 × $110) - (0.50 × $100)
- EV = $55 - $50 = +$5
This is a +EV bet. Over thousands of flips, you'd average $5 profit per bet.
Why It Matters
Every casino game has a negative expected value for the player — that's the house edge. The goal of professional sports bettors is to find +EV opportunities where the odds offered are better than the true probability of the outcome.
Key Insight
A single bet's result tells you nothing about whether it was a good bet. A +EV bet can lose, and a -EV bet can win. What matters is the long-term mathematical expectation. This is why sample size matters and why bankroll management is essential.