Every casino game is built around one number, and most players never look at it. The house edge is the slice the casino keeps, on average, from every bet you place. It’s not a fee you see at the till. It’s baked into the rules, the payouts, and the odds, so quietly that you can play for years without ever clocking how it differs from game to game.
Once you can read that number, the whole floor looks different. You stop asking “which game is lucky” and start asking “which game costs me least per hour.” That’s the only question that actually matters.
What house edge means in plain terms
House edge is the percentage of each wager the casino expects to retain over the long run. A 1 percent edge means that, on average, for every £100 you bet, the casino keeps £1 and returns £99. You won’t see this on any single spin or hand — short-term swings dwarf it — but over thousands of bets it’s as reliable as gravity.
The flip side of house edge is return to player, or RTP. A game with a 4 percent house edge has a 96 percent RTP. Same fact, two ways of saying it.
The edge varies wildly by game
Here’s the part most people don’t realise: the difference between the best and worst bets in a casino is enormous. Below are typical figures for common games under standard rules. Exact numbers shift with the specific rules and your choices, but the ranking holds up almost everywhere.
| Game | Typical house edge | Notes |
|---|---|---|
| Blackjack (basic strategy) | 0.5% – 1% | Among the lowest, *if* you play correctly |
| Baccarat (banker bet) | ~1.06% | One of the best single bets in the house |
| Craps (pass / don’t pass) | ~1.4% | Cheap if you stick to the simple line bets |
| European roulette | ~2.7% | Single zero |
| American roulette | ~5.26% | Double zero nearly doubles the edge |
| Slots | 2% – 12% | Hugely variable, often hidden |
| Keno | 20% – 30% | Among the worst bets on the floor |
Look at roulette alone. Switching from the American wheel (two green pockets) to the European wheel (one) cuts the edge roughly in half — same game, same bets, but one rule changes everything. That single green pocket is the whole difference.
Why the numbers are so different
A few forces drive the spread:
Player skill. Blackjack’s low edge only exists if you play basic strategy — the mathematically correct move for every hand. Play on instinct and the real edge against you climbs well above the textbook figure. Games with no decisions, like slots or keno, give you no way to improve your odds; the edge is fixed by the maths.
Payout shaving. Casinos build the edge into how they pay winners. In roulette, the true odds of hitting a single number are 37 to 1 on a European wheel, but the casino pays 35 to 1. That two-unit gap *is* the edge. Slots do the same thing invisibly, through the size and frequency of their payouts.
Bet complexity. The flashy, high-payout bets — the centre of a craps table, side bets in blackjack, most keno tickets — carry far worse edges than the plain options. The bigger the advertised jackpot, the worse the underlying odds usually are.
Transparency. Table games have published, checkable odds. Slot machines don’t show you their RTP on the glass, which is exactly why their edge varies so much and skews higher. Independent auditors such as eCOGRA test and certify the payout percentages of licensed online games precisely because players can’t verify them by eye (ecogra.org).
What the edge actually costs you per hour
House edge alone doesn’t tell the full story — speed does too. A game with a low edge played very fast can cost more than a high-edge game played slowly. What matters is edge multiplied by how much you wager per hour.
Roughly: bet £10 a hand at blackjack, play 60 hands an hour with a 0.5 percent edge, and you’re risking about £3 an hour on average. Feed £2 spins into a slot at 600 spins an hour with an 8 percent edge, and the expected cost is around £96 an hour. Same evening, vastly different price tag. The slot isn’t “unlucky” — it’s just expensive by design.
The house edge isn’t the casino cheating you. It’s the price of admission, printed in maths instead of pounds. The mistake is paying a premium price without knowing you’re doing it.
Reading a floor like an operator
If you want your bankroll to last, the priorities follow straight from the table:
- Favour low-edge games with decisions — blackjack with basic strategy, baccarer’s banker bet, the pass line in craps.
- Pick European roulette over American every single time it’s offered.
- Treat slots as paid entertainment, not a value play. They’re fun and fast, but the edge is higher and the speed multiplies it.
- Avoid the worst bets — keno, most side bets, long-shot proposition bets. The payouts look exciting because the odds behind them are bad.
None of this turns a casino game into a winning proposition. Over enough bets, the edge wins; that’s the whole business model, and it’s why the industry is profitable and regulated. The point is to spend your entertainment budget on the cheapest seats rather than the most expensive ones, and to know the price before you sit down.
Bodies like the Gambling Commission publish the rules these games operate under in Britain (gamblingcommission.gov.uk), and if play ever stops feeling like entertainment and starts feeling like chasing, free support is available through GamCare (gamcare.org.uk). The edge is fixed. How much you expose yourself to it is the one part that’s entirely yours to control.
