How Casino Odds Work

Casino odds

Ever wondered what casino odds are and how to read them correctly? This article unravels the probabilities that govern popular games like roulette, blackjack, and slots. Understand how casinos use mathematical principles to maintain their advantage and discover strategies to enhance your gaming experience.

Working in the field, I could see countless gamblers come and go, each hoping to hit the jackpot. That’s why I decided to take you behind the scenes and finally reveal the mathematics of chance behind gambling in this exclusive article on how casino odds work.

Behind the Scene

Whether a land-based or online casino, it may seem like a magical space full of entertainment and chances to win, especially if it is a real casino with its immersive lights, bright sounds, and promising luck.

Behind this sparkling camouflage hides an entirely different world led by fixed mathematical principles. Every single game, from slot machines to blackjack, ensures the house has the edge. Though this specific edge may seem small, it guarantees the house wins in the long run.

How Probability Works

To understand how casino odds work, you should get a grasp of what probability is.

In simple terms, casino odds measure how likely an event will occur. You’ll be surprised, but probability is key in gambling. Even more, each game you play has its own probability, which is essential in determining the odds.

Know the Odds; The House Has the Edge

In plain words, having the edge is to have an advantage. The edge is the percentage of every bet that will be kept in the house in the long run. So, yes, the casino will always win, even if gamblers may win occasionally.

Let’s explore some examples for a better understanding.


Slot machines are the cornerstone of casinos. They are easy to play, imply lots of fun, and attract attention.

To your surprise, they actually provide the highest house edge.

How come?

Their potential to win allures lots of gamblers even though the odds are stacked against them. If you wonder whether this is fair or not, I tend to inform you that a random number generator determines every spin. Still, it ensures the casino’s profit as well.


Let’s speak about classic American roulette. The wheel has 38 numbers, from 1 to 36, 0, and 00. If you bet on a single number, the winning odds are logically 1 in 38. And if you win, the outcome is 35 to 1. That’s when the house edge comes in – the difference between the payout odds, 35 to 1, and true odds, 37 to 1. You should know that the house edge reveals a value of about 5.26%.

For the European roulette, the probability of winning is 1 in 37, and the house edge is 2.70%.


The gambler’s decisions during the game can substantially affect the result. The house edge in this game is about 0.5% for those who use the optimal strategy.

However, it may vary. If you didn’t know, blackjack is regarded as one of the most popular games among players because of the low house edge and better casino odds for players.

Casino Games with the Best Odds

Here’s a table showcasing some casino games with the best odds and their respective house edges:

GameHouse EdgePlayer Odds
Baccarat (Banker Bet)1.06%98.94%
Craps (Pass Line Bet)1.41%98.59%
Roulette (European)2.7%97.3%
Pai Gow Poker1.46%98.54%

Odds Variance

Now you know about probability and house edge. Well, variance is solidly linked to them. To keep it simple – variance shows the short-term fluctuations in the outcome of a game. That’s when you can enjoy winning streaks, even in games with bad odds.

Let’s see how it works in practice:


Why is poker unique among casino games? The answer is simple: you play against other players and not against the house.

What does the house gain then, you may ask. It takes a small percentage from each pot. Skilled players can really win due to their skill and strategy. That’s when variance enters the game.

Still, even for consistently winning players, luck is a short-term factor.

What Gambler’s Fallacy Is

There is one common misconception coming from gamblers who think that past events during the game affect the next outcomes.

Is it true, though?

For instance, in a roulette game, some players think that black should be next if the roulette wheel ends up on red five times in a row, leading to biased betting decisions.

You should know that every spin in part is independent. The casino odds stay the same.

The Psychological Factor in Gambling

If you think casinos, especially physical ones, are places of fun and entertainment, I’ll tell you they are masters of psychology. Their role is to keep you playing until you spend your last cent. You might not have paid attention, but everything works in their favor, from the ambient lighting to sounds and layout. Everything is thought out to the smallest details to provide an engaging environment. And if you are aware of these tricks, you can make them work in your favor.

For example, slot machines can use the near-miss effect to make you think you were so close to winning. Eager players won’t wait long for another turn. It is a purely psychological trick based on the players’ wish to succeed. Or, take loss aversion, when gamblers try so hard to regain their lost winning that they end up with even larger losses.

Odds Probability in Online Gambling

Just like in traditional land-based casinos, the odds play an important part too when it comes to online casinos. The core of online gambling is the Random Number Generator. Those algorithms deliver sequences of numbers randomly generated. Whether card games or slot machines, this system ensures fairness.

Yet – it does not cancel out the house edge, and the odds of each game are still determined by the house edge.

For example, the expected payout over time in online slots usually fluctuates between 92% and 98%. So, the slot game is anticipated to return from $92 to $98. The remaining amount is the house edge.

From my experience as a croupier, I can tell you a few players only really understand how casino odds work. Those who only rely on luck often get disappointed. So, you may think about probability next time you embark on a new game.

To sum up, the mathematics of chance is the core principle of informed gambling. Make well-thought decisions by understanding probability and odds, how the house edge works, and how variance can influence the outcome despite the game odds you get.

Latest posts by Mary (see all)