# What Are the Odds of Winning on a Slot Machine?

Slots machines, as games of chance (rather than skill), are generally more about having fun than they are about making money.

However, there are things you can do to maximize your wins and minimize your losses. For example, by calculating a slot machine’s payout percentage, you can obtain a larger picture idea of how much money you stand to win back. Other tactics include using effective bankroll management techniques, joining a slots club to benefit from its rewards programs, and more.

## What Are the Odds of Winning on a Slot Machine?

Slot machine odds used to be easy to calculate. When you’re dealing with three reels, ten symbols on each reel, and a limited pay table, then it’s just a simple math problem. But the rise of electromechanical slot machines and (later) video slots added some complexity to the situation.

### How Probability Works

Probability has two meanings. One is the likelihood of whether or not something will happen. The other is the branch of mathematics that calculates that likelihood. To understand the odds as they relate to slot machines (or any other gambling game), you have to understand the basic math behind probability.

Don’t worry though. The math isn’t hard. Probability involves addition, subtraction, multiplication, and division, all of which you learned in middle school.

The first principle of probability is that every event has a probability of between 0 and 1. If something has no chance of ever happening, then its probability is 0. If something will always happen, no matter what, then its probability is 1.

Probability is, therefore, always a fraction. It can be expressed in multiple ways, as a decimal, as a fraction, as a percentage, and as odds.

A simple example is a coin flip. The probability of getting heads when you flip a coin is 50%. That’s common sense, but how is it determined mathematically?

You simply take the total number of possible outcomes, and divide the outcome you’re trying to determine the probability of it by that number. There are two possibilities when flipping a coin, heads or tails, but only one of them is heads. That’s 1 divided by 2, which can be expressed as ½, 50%, 0.5, or 1 to 1 odds.

Odds are expressed as the number of ways something won’t happen versus the number of ways that something will happen. For example, if you’re rolling a single six-sided die, and you want to know the odds of rolling a six, you’re looking at 5 to 1 odds. There are five ways to roll something other than a six, and only one way of rolling a six.

When you want to determine the probability of multiple things happening, you use addition or multiplication, depending on whether you want to determine whether one OR the other event will occur, or whether you want to determine whether one event AND the other event will occur.

If you’re looking at an “OR” question, you add the probabilities together. If you’re looking at an “AND” question, you multiply the probabilities by each other.

So if you want to know what the probability of rolling two dice and having one or the other come up with a six, you add the probabilities together. 1/6 + 1/6 = 2/6, which is rounded down to 1/3.

If you want to know the probability of rolling two dice and having BOTH of them come up six, you multiply the probabilities. 1/6 X 1/6 = 1/36.

### How Slot Machine Odds USED to Work

Early slot machines were mechanical devices. They had three metal reels that had ten possible stops each.

To calculate the odds of a single symbol appearing on a reel, you just divide the one symbol by the total number of potential outcomes. So if you had one cherry on a reel, your odds of hitting that cherry were 1/10, or 10%.

To calculate the odds of getting three cherries, you multiple 1/10 X 1/10 X 1/10 and get 1/1000, or 0.1%.

If the odds of hitting that symbol are the same as all the others, then you have 10 possible jackpots you can win, which means that your chances of winning SOMETHING are 10/1000, which is 1%.

Most people wouldn’t play a slot machine that lost 99 times out of 100, though, so slot machine designers added additional, smaller prizes for getting two symbols out of three for certain symbols. And as long as they paid out less in prizes than the odds of hitting those jackpots, then those slots are guaranteed to make a profit in the long run.

For example, if a prize for hitting three cherries was \$1000, you’d be playing a break-even game, but if the prize were \$750, it’s easy to see how the casino would be guaranteed a profit. The difference between the odds of winning and the payout odds is where the casino makes its money.

### How Slot Machines Work Now

Modern slot machines use a computer program called a random number generator to determine the outcomes of the various spins of the reels. This creates an imaginary reel with a number of symbols limited only by the program in question.

A mechanical slot machine with 256 symbols per reel would be huge, too large to play, much less to build. But a computer can create an imaginary reel with 256 symbols per reel and take up no more space than an iPod Shuffle.

To make things even more interesting and entertaining, slot machine designers can program different probabilities for each symbol to come up. Most symbols might come up once every 256 spins, but others might come up twice as often, while still others might only come up half as often.

This enables slot machine designers and casinos to offer slot machine games with far larger jackpots than they were able to when they were limited by mechanical reels. And they’re able to offer these large jackpots and still generate a healthy profit.

### How Does This Relate to Payback Percentages?

The payback percentage is the amount of money that the slot machine is designed to pay out over an enormous number of spins. This number is almost always less than 100%. The difference between 100% and the payback percentage is the house edge, and that’s where the casino makes its profits.

A simple example can help illustrate how this works. Suppose you have a slot machine with three reels with ten symbols on each, and it only pays out when three cherries hit. The odds of winning that jackpot, as we determined earlier, is 1/1000.

If we set the jackpot as \$900, and charge \$1 per bet, the payout percentage for that game will be 90%, or \$900/\$1000. Of course, no one would play a slots game which only paid out once in every 1000 spins, which is why there are various smaller payouts programmed in.

There’s no way to tell what the payback percentage on a particular game is unless you have access to the par sheet for that machine. Casino management has that information, but players never have access to that info.

The best slot machine odds are almost always found in real casinos. If you see slot machines in an airport or a bar, be aware that the payback percentages on those games is much lower than you’ll see in a real casino.

## How to Win at Slot Machines

Everyone would like to know how to win at slots, but the truth is that winning at slot machines isn’t any harder than losing at slot machines. You put your money in the machine, spin the reels, and hope for the best. Slot machines are meant to be fun; they’re not intended to provide the player with an income.

In fact, the reality is just the opposite. Slots are there to provide the casino owners with an income. How that works is one of the subjects of this page.

On the other hand, you can minimize your losses and increase your enjoyment of slots games by understanding how they work. You can also learn which slots pay back the most money. In the long run, the house will still have an edge over you, but understanding how much you can expect to lose in a given venue can help you make better bankroll management decisions.

In fact, it might be a good idea to modify you definition of “winning at slots”. Instead of considering yourself a winner if you bring home a big profit, consider yourself a winner any time you played and had a lot of fun.

### How Slots Work

All slot machines in modern casinos use a random number generator (an “RNG) to determine the results of each spin. An RNG is a tiny computer that does nothing but constantly generate numbers. When you push the spin button, that microcomputer selects a number which determines the outcome. In fact, this happens before the reels have even stopped spinning.

On modern slot machines, the reels are just there for show. From a practical standpoint, you could put a quarter in a machine, push a button, and have the screen flash: “You lose!” or “You win \$10”. The mechanism that determined the outcome would be the same, but who would want to play a game like that, especially if you know that the house has a mathematical edge over the player.

The spinning reels, the sound effects, and the bonus games are all there to make the game more interesting to play. If you don’t like the artwork, the music, or any other aspect of a slots game, don’t bother playing it, because those are the real rewards of playing. The chance of getting lucky and winning a jackpot is a real reward, too, but don’t ignore the other aspects of the game.

The random number generator is programmed to pay back a certain percentage of the money paid into it over a period of time. This period of time is known in gambling math as “the long run”, and it’s a lot longer than most people think. We’re talking about tens of thousands of spins, not dozens or hundreds.

This percentage that’s programmed into these machines is always less than 100%. If a slots game were programmed to pay back more than 100% of the money put into it, it would lose money for the casino.

Casinos aren’t in business to lose money.

The trick is to find slot machines that have the highest payout percentages.

### Which Slots Pay Back the Most Money

If every slot machine game in the world had a payback percentage posted on the machine somewhere, it would be easy to determine which slots pay back the most money. You could limit your play to machines with a payback percentage of over 95% for example.

It’s too bad casinos don’t provide that information on specific games, though.

You can find information about specific locations and their payback percentages, though. Some gambling guides and magazines publish this information. For example, The American Casino Guide provides certified information about the payout percentages in various states. Not all states reveal this information, but it’s not a huge leap of logic to expect better payback percentages in states that do reveal this information.

For example, the overall payback percentage for slots in Black Hawk, Colorado is 92.8%. In Central City, Colorado, it’s 92.93%, and in Cripple Creek, it’s 93.66%. Alabama doesn’t release the numbers on their payback percentages.

Which casinos do you think offer the better game?

A couple of guidelines hold true no matter where you play, though. One of those is that payouts are better in large cities with lots of gambling. For example, the payouts in Vegas are higher overall than the payouts in Colorado. And the payouts improve when you play for higher stakes. For example, penny slots in Vegas average around 88% to 91%, but dollars slots average between 93% and 96%. Finally, slot machines at airports usually offer the lowest payouts.

What does that mean for the player? It means that over the long run, if you wager \$x on a particular game, you’ll win back \$x times the payback percentage for that machine. If you’re playing a dollar slot machine on the Strip in Las Vegas, for example, and the payout percentage is around 93%, then if you place \$10,000 in wagers, you’ll win back \$9300. You lost \$700.

That’s only a long term mathematical expectation, though. In the short run, anything can happen, and that’s what keeps people playing.