Casino house edge is the share of each bet the game is designed to keep, on average, over a very large number of rounds. If a bet pays less than true odds, that gap is the edge. A 97.30% RTP European roulette even-money bet has a 2.70% house edge. The casino does not need you to play badly. The paytable already does the work.
This page is the English explainer for “what is a casino house edge.” It is not a volatility article (that lives in German at Was bedeutet Volatilität?) and not a bonus-value calculator — use the bonus calculator for wagering maths.
2.70%
EU roulette even-money
5.26%
US double-zero even-money
~0.5%
Blackjack after basic strategy*
100−RTP
house edge on a slot profile
House edge in one formula
On a single-bet game with a published RTP:
House edge ≈ 1 − RTP.
A slot listed at 96% RTP is built to return about $96 per $100 staked over a huge sample. The remaining $4 is the edge (plus any rounding in how the studio states RTP). Short sessions can land far above or below that. Neither house edge nor RTP predicts the next spin.
On table games the same idea is “true probability versus posted payout.” A fair even-money bet would pay 1:1 at 50% win chance. European even-money roulette wins 18/37 of the time (~48.65%) and still pays 1:1 — that gap is 2.70%.
Typical edges (standard maths, not an operator scrape)
| Game / bet | Typical published edge | What changes it |
|---|---|---|
| European roulette even-money | 2.70% | La Partage / En Prison can halve the edge on even-money when zero hits |
| French roulette even-money with La Partage | 1.35% | Only those bets, not insides |
| American roulette (0 and 00) even-money | 5.26% | Extra green pocket |
| Blackjack, common multi-deck, 3:2, basic strategy | about 0.4–0.6% | 6:5 blackjack, H17, extra decks, no DAS raise it |
| Baccarat banker (5% commission) | about 1.06% | No-commission tables use a different rule to recoup |
| Baccarat player | about 1.24% | Tableau is fixed |
| Baccarat tie (8:1) | often ~14% | High payout, rare event |
| Pass line craps | 1.41% | Odds bets behind the line are closer to even |
*Blackjack range assumes a full basic-strategy chart for stated rules. Guessing raises the edge. See blackjack basic strategy. Roulette layout: how to play roulette. Baccarat: how to play baccarat.
These figures are textbook probabilities for the named rule set. Live tables can add commission, side bets, or 6:5 blackjack. Always read the felt.
How casinos make money (including poker)
Slots and table games: the paytable or the wheel.
Poker rooms usually do not play against you. They take rake — a fee from the pot or a time charge — and sometimes a tournament fee. That is still a house product; it is just collected as a service charge rather than as a banker hand. Casino hold’em and similar branded games go back to a banker edge. Details sit in how to play poker.
Bonuses do not erase edge. Wagering forces extra spin volume through games that still have an RTP below 100%. Price that in the bonus calculator.
Bankroll example (£10 / $10 / €10)
Stake $10 on a 2.70% edge even-money roulette bet. Expected loss per spin is $0.27. After 100 spins at $10, expected loss is about $27 — not a promise you will lose $27, only the long-run centre of the distribution. A lucky streak can finish up; the edge is still there on the next spin.
High-volatility slots with a similar RTP can sit below that centre for a long time, then pay in a burst. RTP and edge describe the centre, not the path. German-language volatility copy: RTP und Volatilität.
No system removes the edge
Martingale, Fibonacci and “due numbers” change the shape of wins and losses. They do not change the expected value of each spin. A table limit or a busted bankroll ends the progression. Roulette betting-system myths are covered in the roulette guide.
House edge vs RTP vs volatility
- House edge — what the house keeps, on average.
- RTP — what the game is designed to return (usually 100% minus edge on a slot profile).
- Volatility — how bumpy the path is. Two 96% slots can feel nothing alike.
None of the three is a session guarantee. Demo play on free slots is for rules and feel, not for predicting cash results.
Short questions
Q: What is a casino house edge?
A: The built-in mathematical advantage in a bet or game, usually 100% minus RTP on slots, or true odds minus posted payouts on tables. The casino is designed to keep that share over a large number of rounds.
Q: Is a lower house edge a way to make money?
A: No. A smaller edge slows the expected drain. It does not flip the expectation to the player on a standard casino product.
Q: Do inside roulette bets have a higher house edge than outside bets?
A: On a single-zero European wheel the edge is 2.70% on most bets (the basket-style “0-1-2-3” on American wheels is worse). Inside bets pay more when they hit and lose more often; the edge per unit staked is the same on the standard insides.
18+ (21+ where required). Gambling can be addictive. This guide is educational maths, not a prediction and not a recommendation to play for real money. Help: responsible gambling. Track a session in the bankroll tracker.