Expected Value (EV)
The single most important concept for making smart gambling decisions.
Expected Value (EV) is the mathematical average of what you'll win or lose on a bet over the long run. It's the single most important concept for understanding gambling— and the foundation for every smart betting decision.
What Is Expected Value?
EV answers the question: "If I made this bet a million times, how much would I win or lose per bet on average?"
This calculates the weighted average outcome of a bet.
Example: Coin Flip Bet
Someone offers you a bet: flip a fair coin. Heads you win $11, tails you lose $10.
On average, you win $0.50 per flip. This is a +EV bet—you should take it every time.
Strategy Insight
EV in Casino Games
In casino games, EV is almost always negative—that's the house edge.
On a $10 bet on red in American roulette, you lose $0.53 on average. The house edge is 5.26%.
Good to Know
Finding +EV Opportunities
While most gambling is -EV, there are exceptions:
✓ Promotions and Bonuses
Some bonuses with low wagering requirements can be +EV when played optimally.
✓ Poker vs. Weak Players
Poker is player vs. player. Skilled players have +EV against weaker opponents.
✓ Sports Betting (with Edge)
Finding mispriced lines can create +EV opportunities, but it's extremely difficult.
✓ Card Counting
When the deck is rich in high cards, blackjack becomes +EV (and casinos will ban you).
EV vs. Variance
Understanding the difference is crucial:
- EV tells you what to expect in the long run
- Variance tells you how much results will swing in the short run
A -EV game with high variance can produce winning sessions. You might win on slots (high variance) but lose on blackjack (low variance) in a single night— even though blackjack has better EV.
Warning
Applying EV to Decisions
Use EV thinking beyond gambling:
- Should I pay for that extended warranty? (Usually -EV)
- Should I buy lottery tickets? (Extremely -EV)
- Should I insure my blackjack hand? (Almost always -EV)
Strategy Insight
Return to Player (RTP) by Game
Higher is better for the player
Key Takeaways
- 1EV is the average outcome of a bet over many repetitions
- 2+EV bets are profitable long-term; -EV bets cost you money
- 3Most casino games are -EV by design (the house edge)
- 4Variance causes short-term swings, but can't overcome long-term EV
- 5+EV opportunities exist in promotions, poker, and finding mispriced lines