Expected value turns odds and payouts into one comparable number.
EV answers: if this exact decision were repeated under the same model many times, what average result would the probability-weighted outcomes imply?
A tiny example
Imagine a $1 bet that wins $1 profit 49% of the time and loses $1 51% of the time.
EV = (0.49 × +$1) + (0.51 × −$1) = −$0.02.
The expected value is −2 cents per $1 wagered, equivalent to a 2% expected loss on the initial wager.
Negative EV does not mean “you cannot win.”
It means the average result of repeated identical trials is negative. A player can win one trial, ten trials, or an entire session. The distinction between possible and expected is essential.
Poker adds another layer
In poker, EV can depend on opponent ranges, fold probability, future betting, rake and imperfect information. The arithmetic is still useful, but the inputs are estimates rather than a fixed casino paytable.