What is the casino house edge?

The house edge is a fundamental concept in gambling. It is what enables gambling establishments to generate long-term profits, even if players win from time to time. In this article, we explain what it means in practical terms, how it is calculated and what it means for gamblers, both online and in land-based casinos.

Definition of the house edge

The house edge is the average percentage that the casino is expected to win on each bet over the long term. It’s a mathematical margin built into every game, from blackjack to roulette to slots. 

Some machines, particularly slots, do not display the house edge, but instead give you the ‘RTP’ or ‘Return to Player’ with a percentage. This amount represents the % of money returned to players on average, so the remaining % is the house advantage.

Here are two examples to help you understand: 

• In a game with a house edge of 2%, for every €100 wagered, the casino wins an average of €2, while the player wins an average of €98.
• In a game with an RTP of 96%, the player wins an average of €96 and the house edge, which is 4%, represents a gain of around €4 for the casino.

We can conclude from this that the lower the house advantage, the greater your chances of winning in the short term.

How is the house edge calculated?

Each casino has its own rules and probabilities. Developers and mathematicians use this data to calculate the advantage. Some are fixed, as in roulette or baccarat, while others are set by the game’s creator, as in slot machines and dice games.

Here are the fixed house advantages: 

• European roulette: approx. 2.7%
• American roulette: approx. 5.26%
• Blackjack (with basic strategy): approx. 0.5% to 1%
• Baccarat: approx. 1.06% for the bank

For slot machines in Belgium, the house advantage is between 2% and 10% for online slot machines, and between 10% and 20% for a slot machine in a physical casino. It is therefore more advantageous for the player to play online than in a gaming room.

Concrete examples

Game	Average house edge	Remarks
European roulette	2,7 %	Better choice than the US version
American roulette	5,26 %	For thrill-seekers
Blackjack	0,5 % à 1 %	With optimal strategy
Baccarat	1,06 %	One of the games with the lowest house edge
Online slots	2 % à 10 %	Highly variable depending on the game

Why is it important for players to know the house edge?

Checking the house edge or RTP of a game before you play it can help you avoid unpleasant surprises, choose the most favourable games and manage your bankroll.

The important thing to remember is that even games of chance are never completely neutral. The casino always has a slight edge, built into the system.

Can you beat the house edge?

It is mathematically impossible to beat the house edge in the long run, except with certain techniques such as :

• Card counting in blackjack (forbidden in most casinos)
• Attractive promotions and bonuses
• Intelligent betting management to limit losses

But this remains marginal. The main thing is to play responsibly, for fun, and not for profit.

The house advantage is not a trap, it’s a reality built into all casino games and allows casinos to continue to offer you ever more fun games. Understanding this means being a more informed player, able to make more strategic choices. At Gambling Club, we help you decipher the mechanics of online gambling so you can play with complete transparency.