Why Does the House Always Win? A Look at Casino Profitability

There’s one certainty in gambling: Nothing is left to chance. In the end, the house always comes out the winner. A casino is a business, not a charitable organization throwing free money away. Like any other business, it has a business model in place designed to ensure its profitability.

The House Edge

No matter what game you choose to play, the odds of the casino winning your money are greater than the odds of you winning the casino’s money. That’s because all casino games are designed to provide the house with a built-in edge, diminishing the chances and sizes of potential payouts.

For example, a roulette wheel is numbered from one to 36, so you might think this puts the odds for winning a single number bet at 36 to one. However, roulette wheels also have a zero, and sometimes they have a double zero and even a triple zero. The actual odds of winning are thus 37 to one, 38 to one, or 39 to one, not 36 to one.

The house edge, which is the odds advantage in the casino's favor, represents the average gross profit that the casino can reliably expect to make from each game. On the games with the lowest house edge, a casino might be generating a meager profit of anywhere from around 0.5% to a bit over 2%. On other games, it may make profits of anywhere from 15% to 40%.

The casino isn’t aiming to bankrupt a player in one sitting. The goal is to give the player hope, keep them coming back, and over the long run gradually empty their pockets.

How Players Lose More Than They Expect

Many people who are aware of the house edge still don’t really grasp its implications for their bankrolls. They believe that the roughly 5% edge that the house has at the roulette table means that they can reasonably expect to sit down with $100, gamble for a few hours, and the odds are that they will only lose about $5. They fail to understand that the house edge applies not to their starting bankroll but to the total amount that they wager.

For example, assume a person is making $5 bets on every spin of the roulette wheel, and the wheel spins 50 times an hour. While the person betting may be winning some bets and losing other bets, they are wagering $250 an hour. If the house edge plays out perfectly, at the end of four hours of play they lose $50, or 5% of $1,000—an amount 10 times greater than they had expected.

The Extra House Edge

The longer you play, the greater the odds are that the result of your play will match up with the house edge. A player may be ahead in the short term. However, over the long haul, the house edge eventually will grind them down into unprofitability.

That’s why casinos do all they can to keep you playing longer. For example, casinos are famous for lacking clocks and windows. They’re designed that way to keep players unaware of the passage of time.

Many first-time players are pleasantly surprised at being offered free drinks by the management. Those complimentary libations will cost you, though, as being inebriated usually doesn’t improve judgment when it comes to betting.

The Bottom Line

Although all the laws of probability are in the casino’s favor, the house edge varies significantly among the different casino games. The games with the lowest advantage to the casino are usually blackjack and video poker, while the game more stacked in their favor is usually keno.

The smallest edge only applies if the player is playing the odds perfectly, which few people do. The house edge increases as players wager less expertly. American roulette remains one of the most popular casino games, but it carries a 5.26% edge for the house. The house edge on slot machines goes as high as 15%; for keno, it is a massive 40%.