House edge is a term that comes up often when you read about gambling and play various casino games at slotsuk.co.uk. Understanding what it is and how it works is crucial to knowing what your chances of winning the game are. House edge also tells you a lot about how much profit a casino makes from the game.
What is house edge?
House edge is a percentage that describes the advantage that a casino has over players in a particular casino game. It tells you how much of every bet the casino expects to keep on average over a very large number of rounds. The higher the house edge, the larger the advantage for the house, and the more a player can expect to lose over time.
The house edge exists because casino games pay winning bets at slightly less than their true odds. In European roulette, for example, a bet on a single number has a 1 in 37 chance of winning, but pays 35 to 1 rather than the 36 to 1 that would make it a fair bet. That small gap, repeated across every spin, is the casino’s margin.
How to use the house edge: expected loss
The most practical way to read a house edge is to turn it into an expected loss for a session:
Expected loss = total amount wagered × house edge
Suppose you play 100 spins of European roulette at $10 per spin. You wager $1,000 in total, and with a house edge of 2.70% your expected loss is $27. Play the same session on American roulette and the expected loss rises to about $53.
Two points are worth remembering. First, it is the total amount wagered that counts, not your deposit: re-betting the same money many times increases the total. Second, the expected loss is an average. In any single session you can win or lose far more, but over enough play the result tends towards this figure. No betting system changes it.
House edge versus RTP
Slots and video poker usually quote a return to player (RTP) figure instead of a house edge. They are two sides of the same number: house edge = 100% minus RTP. A slot with an RTP of 96% has a house edge of 4%.
House edge in popular casino games
The tip to reducing your expected losses is to play games and bets with a low house edge. The edge varies not only from game to game but between bets within the same game, so the figures below are worth knowing before you sit down.
1. Roulette
Roulette is a casino classic, and there are two main versions. European roulette has a single zero and 37 pockets, giving the casino an edge of 2.70% on almost every bet. American roulette adds a double zero, taking the wheel to 38 pockets and the edge to 5.26%. The five number bet on 0, 00, 1, 2 and 3, only available on the American wheel, is worse still at 7.89%.
Some European tables apply the la partage or en prison rule, which returns half of an even money bet when the ball lands on zero. That lowers the edge on even money bets to about 1.35%, making it one of the best bets in the casino.
2. Craps
House edge in craps depends entirely on the bet, and its range is the widest of any table game. The core bets are among the best value in the casino:
- Pass line: 1.41%
- Don’t pass: 1.36%
- Odds bet placed behind a pass or don’t pass bet: 0%, because it pays at true odds
The proposition bets in the middle of the table are much worse. Hardways carry an edge of 9.09% to 11.11%, and “any seven” carries 16.67%.
3. Blackjack
Blackjack is loved by players around the world because it can offer one of the lowest house edges in the casino, but only when played well. With perfect basic strategy and good rules, the edge is typically around 0.5% or a little less. A player who ignores strategy and plays on hunches faces an edge several times higher.
The rules make a real difference:
- A blackjack that pays 6 to 5 instead of 3 to 2 adds about 1.4 percentage points to the house edge. It is the single most important rule to check.
- Games where the dealer hits a soft 17 give the house slightly more than games where the dealer stands.
- More decks generally mean a slightly higher edge than fewer decks.
- Rules allowing doubling after splitting and late surrender help the player.
4. Baccarat
Baccarat offers three main bets. If you bet on the banker, the house edge is 1.06% after the standard 5% commission. The player bet carries 1.24%. The tie, paying 8 to 1, carries 14.36%, which makes it one of the worst bets on the casino floor despite its attractive payout.
5. Slots
Slots are probably the most popular casino game. They are easy to play and many players choose them in the hope of a large jackpot. Each slot has its own return to player percentage, set by the game designer. Online slots commonly have an RTP of around 94% to 97%, which means a house edge of roughly 3% to 6%. Some games are released in several versions with different RTPs, and the operator chooses which one to offer, so check the RTP in the game’s information screen at the casino where you play.
Progressive jackpot slots usually have a lower base RTP, because part of every stake funds the jackpot. Remember too that RTP is a long run figure: on a high volatility slot, a short session can end far from it in either direction.
6. Video poker
Video poker combines a fixed, published paytable with player decisions, so the house edge can be calculated exactly. A “full pay” Jacks or Better machine, paying 9 for a full house and 6 for a flush, returns about 99.54% with perfect strategy, an edge under 0.5%. Reduced paytables on the same game raise the edge considerably, so the numbers on the paytable are worth reading.
7. Keno
Keno is one of the most expensive games you can play. House edges of 25% or more are common, meaning the casino keeps a quarter or more of every stake on average. It is played for the chance of a big win on a small ticket, not for value.
House edge at a glance
| Game and bet | Approximate house edge |
|---|---|
| Craps odds bet | 0% |
| Blackjack, basic strategy, good rules | about 0.5% |
| Video poker, full pay Jacks or Better | about 0.46% |
| Baccarat, banker | 1.06% |
| Baccarat, player | 1.24% |
| Craps, pass line | 1.41% |
| European roulette | 2.70% |
| Online slots | roughly 3% to 6% |
| American roulette | 5.26% |
| Baccarat, tie | 14.36% |
| Keno | often 25% or more |
What the house edge cannot tell you
A low house edge means lower expected losses, not a guarantee of winning. Every game in the table above favours the casino except the craps odds bet, which is only available alongside a bet that does favour the casino. Treat gambling as paid entertainment, set a budget and a time limit before you start, and never chase losses. Online gambling is for adults aged 18 and over, or the legal age in your country. If it stops being fun, free confidential help is available from organisations such as GamCare and BeGambleAware in the UK and the National Council on Problem Gambling in the United States.