Every casino game is a math problem disguised as entertainment. The flashing lights, the spinning wheels, the clatter of chips — they all do their job. But beneath every spin, shuffle, and roll is a number the casino never puts on a sign: the house edge. It’s not hidden. It’s not a secret. And once you understand it, you’ll never look at a slot machine or a blackjack table the same way again.
What Is the House Edge?
The house edge is the average percentage of every wager the casino expects to keep over the long run. It’s baked into the rules of each game — a small mathematical tilt in the casino’s direction that guarantees profit across thousands or millions of bets.
If a casino offered perfectly fair odds on every game, it would break even. No profit means no casino. The house edge is the thin margin that pays for the building, the staff, the lights, and keeps the business running. It’s typically expressed as a percentage of each wager, and it’s the single most important number a player can know.
House edge is the inverse of Return to Player (RTP). A game with a 5% house edge has an RTP of 95%. Over enough bets, players get back about 95 cents of every dollar wagered, and the casino keeps about a nickel. Online casinos and game developers publish RTP figures more often than house edge, but they’re the same thing viewed from opposite sides of the table.
House Edge at a Glance
Here is how the most popular casino games stack up. These figures assume standard rules and optimal play where skill matters.
| Game | House Edge | RTP | Skill Matters? |
|---|---|---|---|
| Blackjack (basic strategy) | 0.5% | 99.5% | Yes |
| Baccarat (banker bet) | 1.06% | 98.94% | No |
| Craps (pass line / don’t pass) | 1.36–1.41% | 98.6–98.64% | No |
| French roulette (la partage) | 1.35% | 98.65% | No |
| European roulette | 2.70% | 97.30% | No |
| Video poker (optimal play) | 0.5–2% | 98–99.5% | Yes |
| American roulette | 5.26% | 94.74% | No |
| Slots (most machines) | 4–15% | 85–96% | No |
| Keno | 20–40% | 60–80% | No |
How the House Edge Is Calculated
The math is simpler than most people expect. Every game has a fixed set of possible outcomes, each with a known probability. The casino sets its payouts just below what fair odds would demand. The gap between fair odds and actual payouts is the house edge.
Roulette as a Worked Example
European roulette has 37 pockets: numbers 1 through 36 plus a single zero. A straight-up bet on one number pays 35 to 1. The true odds of hitting that number are 1 in 37, which would justify a payout of 36 to 1. The casino pays 35 to 1 instead. That one-number gap is the entire house edge.
The formula: Edge = (37 − 35 − 1) ÷ 37 × 100 = 2.70%. That 2.7% applies to nearly every bet on the table, whether you are betting on a single number or on red.
American roulette adds a double-zero pocket, bringing the total to 38. The payout stays at 35 to 1, but the denominator changes: Edge = (38 − 35 − 1) ÷ 38 × 100 = 5.26%. That extra pocket nearly doubles the casino’s take.
Why Blackjack Rules Change Everything
Blackjack’s house edge shifts dramatically with rule variations. A single-deck game that pays 3:2 on blackjack, lets the dealer stand on soft 17, and allows doubling after split produces a house edge of about 0.5% with basic strategy. Switch to six decks, pay 6:5 on blackjack instead of 3:2, and make the dealer hit soft 17, and the edge climbs above 2%. The same game, played at different tables, can cost four times as much — which is why checking the specific rule set matters more than most casual players realize.
Blackjack: The Lowest House Edge in the Casino
Blackjack consistently offers the best odds for players — around 0.5% when you use basic strategy. The casino expects to keep 50 cents for every $100 wagered over the long run.
That number is conditional. Without basic strategy, the edge climbs to 2% or more. Strategy charts are freely available, and memorizing one takes most people an afternoon. The bigger trap is 6:5 blackjack tables, which have become common on some casino floors. A 6:5 payout on a natural blackjack sounds small as a change but nearly triples the house edge. Players should always verify the blackjack payout before sitting down.
Card counting can theoretically flip the edge in the player’s favor, but modern casinos make it far harder than the movies suggest — automatic shufflers, multi-deck shoes, and continuous surveillance are standard. Even so, the math of blackjack is the reason it attracts more skilled players than any other table game.
Roulette: Pick Your Wheel
Roulette is pure chance, and the house edge depends entirely on which wheel you play.
- American roulette — 38 pockets including 0 and 00. House edge: 5.26% on all standard bets.
- European roulette — 37 pockets, single zero only. House edge: 2.70%.
- French roulette — European wheel plus la partage or en prison rules on even-money bets. House edge: 1.35% on those bets.
The difference adds up fast. A player betting $100 per spin on American roulette loses about $5.26 per spin on average; the same bet on a European wheel loses $2.70. Over a hundred spins, that’s a $256 difference. European and French roulette are widely available, especially at online casinos — checking for a single-zero wheel is the single most important roulette decision a player can make.
Craps: Great Odds on the Simple Bets
Craps looks like controlled chaos, but the core bets have some of the best odds on the floor. The key is knowing which bets to make and which to skip.
- Pass line: 1.41% house edge
- Don’t pass: 1.36% house edge
- Free odds bet (behind the line): 0% — the only bet in the casino with no house edge
- Proposition bets (any 7, hard ways, hop bets): 5% to 16% house edge
The free odds bet is unique. Casinos allow it only as a supplement to a pass or don’t pass bet, but it pays at true odds with no built-in edge. Taking maximum odds when the casino offers them is the single smartest move a craps player can make. Everything else on the table — especially the prop bets in the center — feeds the house at several times the rate of the basic line bets.
Baccarat: Banker Is Almost Always the Right Call
Baccarat carries a reputation as a game for high rollers, but mathematically it is one of the most affordable. The banker bet has a house edge of 1.06%. The player bet sits at 1.24%. The tie bet is 14.36% — a number that should make any informed player skip it entirely.
A 5% commission on winning banker bets nudges the effective cost higher, but it remains the best wager on the table. The game itself requires no decisions after the bet is placed, making it a pure game of chance with unusually favorable odds.
Slots: The Most Expensive Entertainment in the Casino
Slot machines generate more revenue for casinos than every other game combined. They are fast, easy, and carry the widest range of house edges — typically 4% to 15%, and sometimes higher.
Each machine has its RTP set by the game developer. Online slots publish this number openly in the game information screen; land-based machines are less transparent. Players who want the best shot should look for machines with RTP of 96% or higher (4% house edge or lower). Even then, the speed of play works against you — a slot player making 600 spins per hour at $1 per spin cycles $600 through the machine. At a 5% house edge, the expected loss is $30 per hour, whether you win or lose individual spins.
Poker: The One Game Where the House Isn’t Your Opponent
Poker breaks every pattern on this list. You are not playing against the casino — you are playing against other players. The house collects a rake, a small percentage taken from each pot or a flat fee per hand, regardless of who wins.
The effective house edge in poker depends entirely on the skill of the players at the table. A strong player facing weaker opponents can expect to win over time, something that is mathematically impossible in roulette or slots. This is why poker attracts a different kind of player — people who view it as a skill-based competition where the casino is just the venue, not the opponent.
How to Use This Information
Understanding the house edge will not help you beat the casino. The math guarantees that nobody beats the house in the long run on any game where you play against it directly. What it does is help you make smarter decisions about where to spend your entertainment budget.
- Stick to games with a low house edge. Blackjack, baccarat (banker bet), craps (pass/don’t pass), and European or French roulette give you the most play for your money.
- Learn basic strategy for blackjack and video poker. Optimal play cuts the house edge by a factor of two or more compared to guessing.
- Avoid sucker bets. The tie bet in baccarat, proposition bets in craps, and most side bets in blackjack carry double-digit house edges.
- Check the rules before you play. A 6:5 blackjack table or an American roulette wheel changes the math significantly. Know what you are playing.
- Treat gambling as entertainment cost. The house edge is not a guarantee of loss on any single visit, but it is a reliable predictor of what happens over time. Set a budget, stay within it, and stop when the fun stops.
Frequently Asked Questions
Can you overcome the house edge?
On games of pure chance — roulette, slots, craps, baccarat — no. The edge is mathematical and unavoidable over the long run. Short-term wins are common, but the longer you play, the closer your actual losses will converge to the expected house edge. In blackjack and poker, skill can reduce or temporarily reverse the edge, but the casino’s structural advantages (rule variations, the rake, surveillance) keep the long-term math in their favor.
What casino game has the lowest house edge?
Blackjack played with basic strategy (about 0.5%) and baccarat’s banker bet (1.06%) are the best bets among standard casino games. Some video poker variants can dip below 0.5% with perfect play. Craps pass and don’t pass at 1.36–1.41% are close behind.
What game has the highest house edge?
Keno is the worst, typically ranging from 20% to 40%. Some slot machines and casino side bets also carry house edges above 15%. The tie bet in baccarat (14.36%) and proposition bets in craps (up to 16%) are among the worst common wagers.
Does the house edge mean I will always lose?
No. The house edge is a long-term statistical average. Individual sessions can swing wildly — a player can win ten hands in a row, hit a slot jackpot, or have a hot streak at the craps table. The edge becomes reliable only across thousands or millions of bets. In the short term, luck dominates. That’s what keeps the games interesting.
Is house edge the same as the casino’s profit margin?
Not exactly. House edge is the theoretical advantage built into a game. The casino’s actual profit is called the hold percentage, and it is usually higher than the house edge because players make mistakes, play suboptimally, and leave the table before the long-term average kicks in. The house edge is the floor; the hold is what casinos actually collect.