What Is the House Edge?
The house edge is the mathematical advantage a casino holds over players in any given game. Expressed as a percentage, it represents the average amount of each bet that the casino expects to retain over the long run. For example, a game with a 5% house edge means that, on average, the casino keeps $5 for every $100 wagered — though short-term results for any individual session can vary widely.
Understanding the house edge doesn't mean you'll always lose — it's a long-run statistical measure, not a prediction for any single session. But it does help you make smarter choices about which games to play.
Why Casinos Always Have an Edge
Casinos are businesses, and every game is designed so that the odds slightly favour the house. This is achieved in different ways depending on the game:
- In roulette: The zero (and double zero in American roulette) gives the house its edge, since bets on red/black or odd/even don't cover zero.
- In slots: The Return to Player (RTP) percentage determines payouts — a 96% RTP means the machine returns 96 cents of every $1 wagered on average.
- In blackjack: The house edge comes from the fact that players act before the dealer, meaning player busts result in immediate losses even if the dealer later busts too.
House Edge by Game Type
| Game | Approximate House Edge |
|---|---|
| Blackjack (with basic strategy) | 0.5% – 1% |
| Baccarat (Banker bet) | ~1.06% |
| European Roulette | ~2.7% |
| American Roulette | ~5.26% |
| Video Poker (optimal play) | 0.5% – 2% |
| Online Slots | 2% – 10%+ |
| Keno | 20%+ |
Note: These figures are general approximations. Actual house edges vary by platform, variant, and ruleset.
RTP vs. House Edge
You'll often see slots and video poker games advertised with an RTP (Return to Player) percentage rather than a house edge. These two figures are simply two sides of the same coin:
- RTP of 96% = House edge of 4%
- RTP of 98% = House edge of 2%
When comparing slot games, always look for higher RTP values — they indicate more of your wagered money is statistically returned in winnings over time.
How Variance Affects Your Experience
The house edge tells you the long-run average, but variance (also called volatility) describes how wildly results can swing in the short term. A high-variance slot might go long stretches without paying out, then deliver a large win. A low-variance slot pays out more frequently but in smaller amounts.
Both types have a house edge — but the experience of playing them is very different. Understanding this distinction helps you choose games that match your bankroll and playing style.
Practical Takeaways
- Prefer games with a lower house edge to extend your playing time and reduce average losses.
- Learn the optimal strategy for skill-based games like blackjack or video poker to minimise the house edge further.
- Check the RTP of slot games before playing — most reputable platforms display this in the game information.
- Avoid high house-edge games like Keno if you're trying to make your bankroll last.
- Remember: the house edge is calculated over thousands of rounds — a single session can go very differently in either direction.
The Bottom Line
The house edge isn't something to fear — it's simply a feature of how casino games are designed. Armed with this knowledge, you can make more informed decisions, choose games that offer better value, and approach your sessions with realistic expectations. Smart players don't ignore the house edge; they factor it into every decision they make.