Casino Games Explained: Rules, Odds and House Edge

The figures below are the standard published values for each bet with the usual rules. Online variants can differ, so check the game’s help screen, where licensed sites show the rules and return.

Slots are not in the table because each game sets its own return. A slot’s RTP is fixed by its maths model and published in the game rules, and many titles come in several RTP versions, so the same slot can return different amounts at different sites.

Our old roulette page praised particular crypto sites. What matters more is which wheel you face.

The wheels

• European: 37 pockets, numbers 1 to 36 plus a single zero.
• American: 38 pockets, adding a double zero. The payouts stay the same, so the extra pocket nearly doubles the edge.
• French: a European wheel, often with la partage or en prison on even-money bets, which halves the edge on those bets.

Bets and payouts

Notice the pattern. Every bet is priced as if the wheel had 36 pockets, and the zero is the casino’s margin. That is why no combination of bets, and no betting system, changes the 2.70% edge on a European wheel.

Why systems do not work

The Martingale, doubling after each loss, looks safe on paper. Start at £5 on red and lose seven spins in a row, and your eighth bet is £640, with £635 already lost. On a European wheel, the chance of seven non-red results in a row is (19/37) to the power of 7, about 1 in 106, and table maximums can stop the doubling before you recover anyway. The system trades many small wins for rare, very large losses, and the long-run edge is unchanged.

Blackjack is the one common game where your decisions change the edge noticeably. You and the dealer each aim for a total closer to 21 than the other without going over; number cards count face value, picture cards count 10, and an ace counts 1 or 11. A two-card 21 is a blackjack and traditionally pays 3 to 2.

Played on instinct, the edge is often several percent. Played with basic strategy, the chart of mathematically best decisions for each hand, it drops to well under 1% at a fair table. Watch for tables that pay 6 to 5 for blackjack: that single change adds about 1.39 percentage points to the house edge. Our blackjack basics guide covers the rules, the strategy chart and the rule changes to avoid.

Baccarat asks one question: will the player hand or the banker hand finish closer to 9? Cards are dealt by fixed rules, so you make no decisions after placing the bet. Totals count only the last digit, so a 7 and an 8 make 5. The banker bet wins slightly more often than the player bet, which is why a 5% commission is taken from banker wins. Ignore the tie bet: at 8 to 1 it carries an edge above 14%.

Craps looks complicated but the core is simple. On the come-out roll, a pass line bet wins on 7 or 11 and loses on 2, 3 or 12. Any other total becomes the point, and the bet then wins if the point repeats before a 7. Once a point is set, you can add an “odds” bet behind the line that pays true odds with no house edge, which is the closest thing to a free bet in a casino. Proposition bets in the middle of the table, like any seven, carry the highest edges in the game.

Sic bo uses three dice. Big (totals 11 to 17) and small (4 to 10) are the simplest bets and lose on any triple, giving a 2.78% edge. Specific triples pay large odds but cost far more over time.

Crypto dice, a single-number game popular on offshore crypto sites, works differently: you pick a win chance and the site pays a multiplier just below fair odds. With a 1% house edge, a 50% chance pays 1.98x rather than 2x. The edge is set by the operator and shown in the game, so it varies by site.

A slot’s RTP comes from its paytable and reel maths, and it is fixed for the version you are playing. Variance matters as much as RTP: a high-variance slot pays rarely but heavily, so sessions swing more. On progressive jackpot slots, part of each stake feeds the jackpot, and the base game’s return is lower until the jackpot is won.

Online slots at Gambling Commission licensees also carry legal stake limits: £5 a spin for adults, and £2 for 18 to 24-year-olds since 21 May 2025. Our old pages on Bitcoin jackpot and progressive slots now lead here because they promoted sites rather than explaining the games.

Video poker deals a five-card hand from a single virtual deck. You choose which cards to hold, draw replacements once, and are paid according to the final hand. Because the deck is fixed at 52 cards and the paytable is on screen, the return can be calculated exactly for each version.

Paytables are where the edge hides. In Jacks or Better, the full-house and flush payouts are the giveaway: 9 and 6 coins per coin bet gives 99.54% with perfect play, while lower pays on the same two hands cut the return noticeably. Perfect play here means holding the statistically best cards, which is learnable with a strategy chart. The royal flush is rare, roughly once in 40,000 hands with correct play, and much of the quoted return depends on betting the maximum coins so it pays its top amount.

Poker against other players is different from everything above. The house does not bet against you; it takes a rake from pots or a fee for tournaments, and your results depend on how you play against opponents. Casino poker variants played against the dealer, such as Casino Hold’em, do carry a house edge like any table game.

Keno and lottery-style draws sit at the other extreme. Their pay tables vary widely by operator, and the edge is usually far higher than at blackjack, baccarat or roulette. If you play them, find the stated return in the game rules first and compare it with the table games above.

The edge tells you the average; variance tells you how far a session can stray from it. Blackjack shows this clearly. With a 0.28% edge and a standard deviation of about 1.14 units per hand, 100 hands at £5 have an expected loss of £1.40, but the standard deviation of the result is about £57. Roughly 95% of such sessions land between a loss of about £113 and a win of about £111, so the £1.40 average is invisible inside the swings.

Over 10,000 hands the picture changes. Expected loss grows to £140, while the spread grows only to about £571, so the edge becomes a steadily larger part of the outcome. This is why a casino with thousands of players is close to certain to profit, while any one player can have a winning evening. It is also why a winning streak says nothing about a game being “due” or a system working. Each hand or spin is independent, and the maths behind the next one is exactly the same as the last.

1. Choose the lowest-edge version of a game: European over American roulette, 3 to 2 blackjack over 6 to 5, banker over tie.
2. Set a loss limit in pounds before you start, and treat the expected hourly cost as the price of the entertainment.
3. Slow down. Fewer bets per hour mean a lower expected loss at the same edge.
4. Skip side bets, which almost always carry much higher edges than the main game.
5. Use deposit limits and time reminders, which licensed sites must offer. Our safer gambling page lists free UK tools.

For the legal side of crypto and gambling, read UK law and tax. If you came here from one of our old game pages, the status page for our old list explains what happened to the sites they named.