Direct Answer
Expected value (EV) is the probability-weighted average outcome of a bet repeated indefinitely. It is the single most important quantity in gambling mathematics: positive EV bets profit on average, negative EV bets lose on average, and long-run profit is the sum of EVs.
Key Takeaways
- EV is the average payoff of an infinitely repeated bet.
- Long-run profit equals total EV.
- EV is necessary but not sufficient for survival.
Formula and intuition
EV = Σ p(outcome) × payoff(outcome). The intuition: imagine making the same bet a million times. The average per-bet profit is the EV. Individual results are noise; EV is the signal.
Necessary but not sufficient
Positive EV does not guarantee profit on any single bet, in any single session, or even over a small sample. Bankroll and variance management determine whether you survive long enough to realize the edge.
Frequently asked questions
Is EV the same as profit?+
No. EV is the expected profit per bet; realized profit converges to EV only over many trials.
Educational only. Not wagering, financial, or legal advice. See our editorial policy.