What Is the House Edge?
The house edge is the mathematical advantage a casino holds over players in any given game. It's expressed as a percentage of each bet that the casino expects to retain over the long run. It's not a scam or trick — it's a built-in feature of game design that allows casinos to remain profitable while still paying out significant winnings to players.
For example, a house edge of 2% means that for every $100 wagered, the casino expects to keep $2 on average over a very large sample of bets. Individual sessions can swing wildly — players win big all the time — but the math always works in the casino's favor over time.
How the House Edge Is Created
Casinos create their edge in different ways depending on the game:
- Roulette: The zero (and double zero in American roulette) means bets on red/black don't have a true 50/50 chance.
- Slots: The RTP is set below 100%, meaning the machine pays out less than it takes in over time.
- Blackjack: Players act first, meaning they can bust before the dealer even plays.
- Keno / Scratch Cards: Prize pools are set below the total amount wagered.
House Edge by Game Type
| Game | Approximate House Edge | Notes |
|---|---|---|
| Blackjack (Basic Strategy) | 0.5% – 1% | Depends on rules and player skill |
| Baccarat (Banker Bet) | ~1.06% | One of the lowest edges available |
| European Roulette | ~2.7% | Single zero wheel |
| American Roulette | ~5.26% | Double zero increases edge significantly |
| Video Poker (Full Pay) | <0.5% | Requires optimal strategy |
| Slot Machines | 2% – 15% | Varies widely by game and operator |
| Keno | 20% – 35% | Among the highest edges in a casino |
The Difference Between House Edge and RTP
These two terms are directly related. RTP (Return to Player) is simply 100% minus the house edge.
- A slot with 96% RTP has a 4% house edge.
- Blackjack with a 0.5% house edge has an RTP of 99.5%.
From a player's perspective, higher RTP = better value. From the casino's perspective, higher house edge = more profit per dollar wagered.
Why Variance Matters Alongside House Edge
The house edge is a long-term average. In the short term, variance (volatility) plays a massive role. You can win significantly even in high-house-edge games over a short session, and you can lose in low-edge games. This is why:
- Short sessions are unpredictable — winners and losers are determined by luck.
- The longer you play, the more the house edge asserts itself mathematically.
- Bankroll management helps you survive variance long enough to enjoy your session.
Practical Tips Based on House Edge
- Choose European roulette over American whenever possible — the single zero halves the edge.
- In blackjack, learn basic strategy to minimize the house's advantage.
- Avoid high-edge games like keno and certain side bets for regular play.
- Always check a slot's published RTP before playing — reputable casinos list this in the game info.
The Bottom Line
The house edge doesn't mean you can't win — millions of players do every day. It simply means the odds are structured so that, over time, the casino retains a portion of all money wagered. Understanding this helps you set realistic expectations, choose better games, and approach gambling as entertainment rather than a financial strategy.