How Many Different Slot Machine Games Are Available to Play?

3 Duplicate Images of Large Slot Machines in Different Colors With Earth Background

Sometimes I have a hard time coming up with topics to write about, but sometimes I get a brilliant idea – usually in the form of a question I haven’t seen answered anywhere else.

Today I was thinking about the wide variety of slot machine games.

And it made me realize that I’ve never seen a website that tried to come up with a total number of slot machines that exist in the world.

On top of that, how many different kinds of these games are available?

When you factor in the games available online, the number might be more staggering than you’d think.

How Many Casinos Are There in the World?

According to the information I found on, it looks like there are at least 3600 casinos in the world. That’s a statistic from 2011, though, and I think the industry has expanded since then.

Graph Showing Number of Casinos in the World

If you wanted to extrapolate the total number of actual physical slot machines from that number, you’d need to know the average number of slot machines per casino and multiply.

It’s safe to assume that there’s at least an average of one slot machine per casino, so we know there are at least 3600 slot machines in the world.

But we also know that most casinos have more than a single slot machine on the floor.

In Nevada, for example, there’s an estimated total of 165,000 machines throughout the entire state.

Graph Showing Number of Slots in Nevada

Since we know that there are 334 casinos in Nevada, calculating the average number of machines per casino is easy. It’s just 165,000 divided by 334, or 494 slot machines per casino.

Let’s call that 500 slot machines per casino on average.

Let’s also recognize that in some countries, slot machines make up a lower percentage of the gambling games on the floor. (In Macau, for example, 80% of the casino seems to be devoted to baccarat.)

The average worldwide might be 250 slot machines per casino.

If you have 3600 casinos in the world with between 250 and 500 slot machines in each, you have a worldwide total of between 900,000 and 1.8 million slot machines.

But How Many Different Games Are There?

Obviously, not every slot machine in every casino is different from the game next to it. Most casinos have a variety of games available.

Again, we’re stuck making estimates, and here the math is going to get even fuzzier. I’m just not sure how many of each kind of game are available in each casino.

We might be able to make some estimates based on the number of different games available from a single manufacture. The biggest slot machine manufacturer in the world is IGT.

Can we look at their site to see how many different games they make?

When I go to the IGT website and look at their library of games, I see that they claim to have the largest library of slot machine games in the world.

When I do a search of their games, I get the option to choose “all games.” This results in a list of 559 different games.

This is obviously above average, so maybe we can assume that the average number of different games from each manufacturer is much lower than that – let’s call it 200 games per manufacturer on average.

You still can’t extrapolate an average number of different kinds of games per casino, because a lot of casinos are going to have games that are also found in other casinos.

How Many Different Companies Manufacture Slot Machine Games?

When I search for “how many different companies manufacture slot machine games,” the top result claims to list 31 different companies which make slot machine games.

If you assume that each company makes 500 different games, then you can figure that there are at least 15,000 different slot machine games in the world.

It might make sense to assume a lower average, though, since the biggest manufacturer only has a library of 559 games.

Let’s assume an average of 250 games per company instead.

Now we have an estimate of 7500 different slot machine games in the world.

What About Online Slot Machine Games?

It’s still not that easy to answer this question, because it doesn’t account for the number of software companies which make slot machine games that are available exclusively online. Even if you look up the number of different casino software providers online, it gets sticky with overlap.

Some companies make games for both brick and mortar casinos, while others make games exclusively for real money online casinos, and still others do both.

Maybe we can come to a conclusion about a number by just assuming that there are at least as many different online-only slot machine games as there are brick and mortar casino games.

So we’re looking at a likely total of 15,000 different kinds of slot machine games in the world, including both online and brick and mortar casinos.

What kind of growth rate does that imply?

The first slot machine was invented and manufactured in 1895, and at the time, there was just one kind of slot machine game.

That was 125 years ago.

If you assume a steady rate of growth, which probably isn’t at all accurate, you just divide 15,000 games by 125 years.

This means that we see an average of 120 new slot machine games per year.

I suspect, though, that during the first decade of their existence, you saw a much slower growth in the number of slot machines. That growth rate has surely accelerated by now, too.

How Do the Different Kinds of Slot Machines Work?

Obviously, with this many kinds of slot machines available, you’ll see a variety of different game-play features, but the variations are probably fewer than you might think.

At the end of the day, slot machines all have one thing in common:

Spinning reels with symbols on them.

For decades, slot machines used actual physical reels made of metal. These were set into motion using a lever, springs, and gears. This changed in the late 20th century, though, when electromechanical machines became the standard.

Closeup of a Variety of Slot Machines

Now, of course, slot machines are more akin to video games or cartoons than anything else. The reels are still there, and they still spin, but as often as not, they’re just animations on a computer monitor. The outcomes are determined by a computer program called a random number generator (RNG).

The payouts for the various combinations are set in such a way that the casino has a solid mathematical advantage that’s impossible to overcome in the long run.

What Kind of New Features Do Modern Slot Machines Have?

One of the limits to mechanical slot machines was the number of symbols on each reel, each of which usually had an equal probability of showing up on the payline. This limitation was eliminated when a computer program started determining the outcomes.

For example, on a physical slot machine reel, it’s almost impossible to include more than 20 symbols per reel. With 3 reels, this means you have 20 X 20 X 20, or 8000 different combinations. This meant that you could only make a profit if the payouts for each combination added up to less than 8000 coins.

But with a virtual slot machine reel, you might be able to have 40 symbols on a reel.

Or you might be able to have 20 symbols on a reel, but some of the symbols might be programmed to only come up once every 40 spins, while others might come up more often, like once every 10 spins.

The obvious advantage of this is that the casino can offer bigger jackpots – sometimes much bigger.

In some cases, the jackpot can be really big – progressive jackpots grow over time as they’re played, and sometimes they’re even networked with other slot machines. The MegaJackpots slot machine jackpots start at $10 million, which is a huge payout on a game where the minimum bet is $3.

And that’s only the beginning of the new slot machine features available.

Other New Slot Machine Features

Another example of the new slot machine features that are available is the wild symbol. If you’ve played poker in someone’s home, you probably already know that a wild card can substitute for any card in the deck that will improve your hand.

A wild symbol on a slot machine works the same way.

Scatter symbols are also cool. They’re symbols that don’t necessarily need to land on the payline to win.

Many times, on 5-reel slot machine, when you get 3 scatter symbols on the screen at the same time, you win a prize regardless of which payline (if any) they’re on.

The other most popular new slot machine feature is the bonus game. This is an additional game that gets unlocked when you meet certain conditions on the reels. It usually involves a simple guessing game of some kind, but the payouts are entirely random.


How many different slot machines can you play?

I have no firm rules, but I have offered some estimates. I’m confident of one thing, though – there are more slot machines available online and off, than you’ll ever be able to play in your entire lifetime.