What Is the House Edge?
Every casino game — whether a slot machine, a roulette wheel, or a blackjack table — is mathematically designed to return slightly less to players than it takes in. This built-in advantage is called the house edge. It is the casino's guaranteed long-term profit margin, expressed as a percentage of each bet made.
The house edge is the flip side of RTP. If a slot has a 96% RTP, the house edge is 4%. Simple as that.
House Edge Across Popular Casino Games
Different games carry very different house edges. Understanding these differences helps you choose games more wisely:
| Game | Typical House Edge | Notes |
|---|---|---|
| Blackjack (basic strategy) | ~0.5% | One of the lowest available with correct play |
| Video Poker (optimal play) | 0.5% – 1% | Varies greatly by variant |
| Baccarat (Banker bet) | ~1.06% | Straightforward game with low edge |
| Craps (Pass Line) | ~1.41% | One of the better table bets |
| European Roulette | ~2.7% | Single zero wheel |
| American Roulette | ~5.26% | Double zero increases edge significantly |
| Online Slots (average) | 3% – 6% | Varies widely by game title and provider |
| Keno | 20%+ | Very high edge; poor value for informed players |
How the House Edge Works in Practice
Importantly, the house edge does not mean you will lose exactly that percentage every session. In the short term, outcomes are random and you can win or lose far more or less than the edge predicts. The edge is a statistical average that emerges over thousands of rounds.
For example, in European roulette, the house edge of 2.7% means that for every €100 wagered across a large number of spins, the casino expects to keep about €2.70. But any individual spin is still a random event.
The Role of Bet Choices Within a Game
Within a single casino game, different bets can carry vastly different house edges. Craps is a perfect example — the Pass Line bet has an edge of around 1.41%, while a Proposition bet on the same table can have an edge above 11%. Choosing smarter bets within a game is just as important as choosing a lower-edge game.
House Edge vs. Theoretical Loss
You can estimate your theoretical loss over a session using this formula:
- Theoretical Loss = Bet Size × Number of Bets × House Edge %
For example: €1 bets × 500 spins × 4% house edge = €20 theoretical loss over the session. This is a useful way to budget responsibly.
Responsible Gambling and the House Edge
Understanding the house edge reinforces why responsible gambling practices matter. The house always has a mathematical advantage — that is how casinos operate as businesses. Treating casino play as entertainment with a defined, affordable budget is the most informed approach any player can take.
If gambling stops being enjoyable or starts affecting your finances, seek support from reputable organisations such as GamCare or BeGambleAware.