The house edge is the one number that determines how much any casino game costs you to play over time. Here is how it actually works.
The basic definition
The house edge is the built-in mathematical advantage a casino holds over a player on any given bet, expressed as a percentage. A 2% house edge means that, on average and over a large number of bets, the casino keeps $2 of every $100 wagered. It is not a fee taken off each individual bet, it is a long-run statistical average.
Typical house edge by game
| Blackjack (basic strategy) | Roughly 0.5% to 2%, among the lowest in the casino |
| European roulette (single zero) | About 2.7% |
| American roulette (double zero) | About 5.26%, nearly double European roulette |
| Craps (pass line bet) | About 1.4% |
| Slots | Typically 2% to 15%, varies enormously by game and is set by the software, not visible on the reels |
Why it matters more the longer you play
House edge is a long-run average, not a guarantee for any single session. A short session can easily beat the house edge or lose far more than it predicts, the math only evens out over thousands of bets. The practical takeaway is simple, the longer you play any single game, the closer your results trend toward the built-in edge, which is exactly why casinos want you to keep playing.
House edge vs RTP
Return to Player (RTP) is the flip side of house edge, a slot with 96% RTP has a 4% house edge. If you see an RTP percentage listed on a slot, subtracting it from 100% gives you the house edge directly.
FAQ
Which casino game has the lowest house edge?
Blackjack played with correct basic strategy typically has one of the lowest house edges in the casino, often under 1%. Baccarat’s banker bet is also low, around 1.06%.
Can you overcome the house edge with a betting system?
No. Betting systems like Martingale change how you distribute your bets, they do not change the underlying odds of the game, so the house edge remains exactly the same over time.
