Slot Machine Odds versus Blackjack Odds

Slots on the Left Blackjack Table on the Right

Every year, people gamble at a casino for the first time in their lives. Some of that’s because every year someone celebrates a birthday where they’re legally able to gamble for the first time in their lives. Some of it’s just happenstance – I once dated a yoga teacher who was 40 years old who’d never been to a casino before at all.

One of the most important things a first-time gambler should understand is the difference between slot machine odds and blackjack odds.

Slot machines are the most popular game in the casinos, and they’re more popular than the other gambling machines (like video poker games) on the casino floor.

Blackjack is the most popular table game in the casino, and most people at least know the basics – don’t go over 21 but beat the dealer.

What new gamblers need to know is how different the odds in one game are from the other.

And that’s what I cover in today’s post.

How You Measure Odds in a Casino Game

When you compare one casino game with another, you look at a number called “the house edge.” This number represents the mathematical advantage that the casino has over the player based on the difference between the payout for a winning bet and the odds of winning that bet.

The higher the house edge is, the worse the game is for the gambler, and the better it is for the casino. A game with a house edge of 10% means you’ll lose your money to the casino twice as fast as you would playing a game with a house edge of 5%.

Where does the house edge come from though?

I cover that in this next section.

Where Does the House Edge Come From?

With any bet, you get paid out at certain odds. You also have certain odds of winning. If the odds of winning are different from the payout odds, one side has an edge over the other. The difference between the odds of winning and the payout odds is the house edge.

Let’s look at a simplified example:

Let’s say you have a casino that offers a simple game where you choose a number between 1 and 10, and then they do a lottery-style drawing where they randomly select a number between 1 and 10.

Lottery Ticket With Pen Next to It

And let’s assume that you get paid off at 8 to 1 if your number hits.

It’s probably easy to see where the house gets its edge, right?

9 times out of 10, you’ll lose, and the other time, you’ll win 8 units.

Since you lost 9 units and only won 8 units, your net loss is 1 unit.

That unit represents the house edge.

All casino games work similarly, although the math gets more complicated with the rules of the game. But if you want easy casino games with low house edges, we did the work for you and put together this helpful guide.

An Example of a Basic Slot Machine and Its House Edge

The classic example of a basic slot machine is a game where you have 10 symbols on 3 reels. The probability of getting a specific symbol on a reel is 1/10. The probability of getting that same symbol on all 3 reels is 1/10 X 1/10 X 1/10, or 1/1000.

If your payoff for hitting that combination is 900 for 1, and if none of the other combinations pay off, the game has a 10% house edge.

Most slot machines are slightly more complicated than that, and sometimes they’re a lot more complicated than that. They’ll have multiple prize amounts for multiple winning combinations.

But all the prize amounts will be lower than the probability of winning those prizes.

You just add them up to get the overall return for the game. Subtract that from 100%, and you have the house edge for the game.

How the House Edge Makes the Casino Money

Since casino games are random, you can sometimes win more money than you lose even when the odds are stacked against you.

But the longer you play, the closer your results will get to the predicted results.

This is called The Law of Large Numbers.

Most casino gamblers are, by their nature, playing in the short run. An average blackjack player might get in 80 to 100 hands per hour. An average slot machine player might make 500 to 600 spins per hour.

But that’s nowhere near “the long run.”

The long run is a matter of thousands or tens of thousands of bets.

But guess who’s seeing thousands and tens of thousands of bets per day?

The casino.

Limit Omaha Poker Table With Casino Chips and a Hand Holding 4 Cards

Assuming a small gas station sized casino has a dozen slot machine game that are full 3 out of 4 hours every day. How many slot machine spins does that small gas station casino see?

Assume 500 spins per hour on each machine 24 hours a day. That’s 12,000 spins per day per machine.

Now multiply that by 9 – that’s 108,000 spins per day.

That’s a big enough number that on a daily basis, even a small casino is operating in the long run.

When you multiply that by 7 days a week or 30 days a month, you begin to see that the small gas station casino is blowing it up.

They’re practically guaranteed a profit.

And that’s a SMALL casino.

Imagine how many iterations a large casino with 8000 slot machines sees.

What Is the Average House Edge for a Slot Machine?

The average house edge for a slot machine varies widely, and it’s not something you can determine by looking at the machine. The odds aren’t readily available. And since slot machine games use random number generators, you can’t even count the number of symbols to calculate the probability of getting a specific symbol on a specific reel.

In some states, casinos are required to report their payback percentages on their slots to the state. For example, we know that the average return on a penny slot machine on the Las Vegas Strip is about 88%. Subtract that from 100%, and you have the house edge – 12%.

The dollar slot machines on the Strip have a higher payback percentage and a lower house edge. They average a payback percentage of 93% and a house edge of 7%.

What does that mean to the average gambler?

You can calculate your statistically predicted loss using these numbers.

Let’s say you’re playing a dollar slot machine game for 3 coins per spin. You’re betting $3 on every spin. And assume you’re making 500 spins per hour. That’s $1500 you’re putting into action every hour.

If the house edge is 7%, your predicted loss per hour is $105.

In reality, you might win $200 in an hour and lose $400 the next hour – if you play long enough, though, you’ll eventually see results that resemble the predicted loss.

What’s the House Edge for Blackjack?

All the table games in the casino offer a lower house edge than the slot machines. Even the worst of table games, like roulette, have a house edge of around 5%.

But blackjack, as you’ve probably heard, has the lowest house edge in the casino.

The trouble is that the house edge in blackjack varies based on the rules in the casino where you’re playing. With good rules, the house edge might be as low as 0.5%.

2 Games of Blackjack

But that number assumes something else besides good rules.

It also assumes that you’re making the decisions with the best mathematical expectation.

Making the right play on every hand in blackjack is called “basic strategy.” If you don’t play with basic strategy, you’re adding 2% to 4% back to the house edge just by making mistakes that cost you money.

Either way, even with a 4% house edge, blackjack is a better deal than slot machines.

Your Predicted Loss per Hour in Blackjack

At most Strip casinos, you’ll need to bet at least $10 per hand at the blackjack games. This might seem like a lot compared to the $3 bets you’re making at the slot machine we already discussed.

But consider this.

Blackjack, by its nature, means fewer bets per hour.

500 bets per hour at $3 per bet is $1500 in action per hour.

100 bets per hour at $10 per bet is only $1000 in action per hour.

Everything else being equal, the more you risk per hour, the more you can expect to lose per hour.

But everything else isn’t equal. The house edge for blackjack is only 0.5% if you use perfect basic strategy.

This means your expected loss per hour at that blackjack game is only $5.

I don’t know of many slot machines that are so much fun that I’d be willing to spend 20 times as much money playing them.


When you compare slot machine odds to blackjack odds, the winner is clear – blackjack is the better game for the player.

Of course, you could argue that if the house has a mathematical edge, if you play long enough, you’ll lose all your money anyway. It’s just a matter of how long it will take.

But wouldn’t you rather get more time gambling for the same amount of money?

I know I would.

Posted in: SlotsTable Games

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