Expected Value (EV)
The average amount you can expect to win or lose per bet over time.
Expected Value (EV) is the most important concept in gambling mathematics. It represents the average outcome of a bet if it were placed an infinite number of times. A positive EV (+EV) means the bet is profitable long-term; a negative EV (-EV) means the house has the edge.
EV is calculated by multiplying each possible outcome by its probability, then summing the results. Every casino game has a negative EV for players (that's how casinos make money), but sports bettors can find +EV opportunities when a sportsbook's odds don't reflect true probabilities.
Understanding EV is what separates recreational gamblers from advantage players. Rather than focusing on individual wins or losses, sharp bettors evaluate every wager by its expected value.
Formula
EV = (Probability of Winning × Amount Won) - (Probability of Losing × Amount Lost)Example
A coin flip bet paying +110 on heads: EV = (0.50 × $110) - (0.50 × $100) = $55 - $50 = +$5 per $100 bet. This is a +EV wager.
Related Terms
House Edge
The mathematical advantage the casino has over players, expressed as a percentage of each bet.
Implied Probability
The probability of an outcome as implied by the betting odds, including the bookmaker's margin.
True Odds
The actual mathematical probability of an outcome, without any bookmaker margin.
Closing Line Value (CLV)
The difference between the odds you bet at and the final odds at market close.
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