What Is the House Edge?
The house edge is the mathematical advantage a casino holds over players on any given game. It's expressed as a percentage representing the average amount of each bet the casino expects to retain over the long run. It's not a trick or a scam — it's a transparent mathematical reality built into every casino game.
For example, a house edge of 4% means that, on average over a very large number of bets, the casino keeps £4 for every £100 wagered. The remaining £96 is returned to players as winnings.
House Edge vs. RTP: Two Sides of the Same Coin
You may also encounter the term Return to Player (RTP) when playing slots. These two figures are simply inverses of each other:
- If a slot has an RTP of 96%, the house edge is 4%
- If a slot has an RTP of 94%, the house edge is 6%
Both describe the same mathematical relationship — just from different perspectives.
House Edge Across Different Casino Games
Not all casino games are created equal. The house edge varies significantly depending on the game:
| Game | Typical House Edge | Notes |
|---|---|---|
| Blackjack (optimal strategy) | ~0.5% | Varies by rules and strategy |
| Baccarat (banker bet) | ~1.06% | One of the lowest in casinos |
| European Roulette | ~2.7% | Single-zero wheel |
| American Roulette | ~5.26% | Double-zero wheel |
| Online Slots | 3%–6% | Depends on RTP of specific game |
| Keno | 20%–35% | Very high house edge |
Why the House Edge Doesn't Mean You'll Always Lose
The house edge is a long-run average calculated across millions of bets. In any individual session, significant variance means players can and do win. The house edge simply ensures that over enough volume, the casino will profit mathematically.
This is why short sessions with strict win/loss limits can be enjoyable and profitable for individual players — even though the maths always favours the casino over time.
How to Use This Knowledge Practically
- Choose higher-RTP slots: Look for games with 96%+ RTP rather than those sitting at 92–94%
- Understand bonus wagering requirements: Bonuses with high wagering requirements effectively raise your real house edge
- Shorter sessions help: The longer you play, the more the house edge erodes a bankroll
- Compare games: If entertainment value is similar, choose the game with the lower house edge
Where to Find RTP Information
For online slots, RTP is usually displayed in:
- The in-game paytable or information screen
- The game developer's website
- The casino's game description page
If you can't find an RTP figure for a slot you want to play, treat that as a warning sign and look elsewhere.
Final Thought
Understanding house edge doesn't make casino gaming a guaranteed way to win — nothing does. But it does make you a more informed player who can choose games wisely, manage expectations, and get the most entertainment value from every session.