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Slot Machines FAQ

Below we’ve answered some of the most frequently asked questions about slot machines that we’ve seen. Many of these are questions that readers have emailed us with. Others are phrases that we saw in our site’s referral logs—someone types a question into Bing or Google, and we see traffic from the phrase, so we assume that our readers want the answers to these questions.

One aspect of our slots FAQ that we think a lot of readers will enjoy are the links to other sections of our slot machine guide. We’ve tried to provide clear, concise answers to these questions here, but we also link to pages with detailed, comprehensive information on each section from within the body of this page. So you can explore these subjects as deeply as you’d like.

How do slot machines work?

Slot machines are gambling games with spinning reels. When slots were first invented, these spinning reels were mechanical and were set into motion using gears and springs. Modern slots retain the trappings of these earlier games, but they use a computer program called a random number generator to determine their results.

Here’s how that works:

A random number generator is a computer program that cycles through a set of numbers, thousands of times per second. When you push the spin button or pull the lever on a modern slot machine, it stops at whatever number it’s on at that nanosecond. That determines the results you see on the reels.

The spinning is just for effect, in fact. The outcome is determined long before the reels stop spinning.

The reels have symbols on them. The combinations of those symbols determine how much you get paid out. The game is designed so that the house has a mathematical edge over time, though.

Here’s how the house edge works:

The casino and the slot machine designers know what the probability is of getting a certain combination of symbols. They set the payoffs for those combinations in such a way that the casino makes a tiny profit.


You might have a 50 to 1 chance of getting a particular set of symbols. That combination might pay off at 45 to 1.

When you hit that combination, you win money, but over the long run, you’ll lose more often than you’ll win.

We’ll discuss the math behind these games in more detail elsewhere on this page and elsewhere on the site.

What is an annuity?

You’ll usually hear the term “annuity” discussed when talking about lottery winners or when talking about retirement instruments. It’s just a fancy word for a financial instrument that pays out a certain amount of money over a period of time. It comes up when talking about slot machines because of the size of progressive jackpots.

Here’s how a common annuity might work:

You win $1 million on a progressive slot machine. You have the option to take out a cash payment of $750,000, or you can choose an annuity of $25,000 a year for the next 40 years.

Even though you get a million dollars with the annuity option, the cash payment is the better option. That’s because of the time value of money. Over 40 years, with wise investing and budgeting, $750,000 will be worth more than $1 million.

There are several companies which take advantage of gamblers who have gotten an annuity through the lottery or a progressive jackpot win.

Here’s what happens:

A player wins a million dollars and takes the annuity. Since the player won a life-changing jackpot, she starts changing her lifestyle. She loans people money. She moves into a bigger house. She buys a nicer car.

But $25,000 a year isn’t a lot of money. It doesn’t take long for someone who doesn’t have experience managing money to run through their available cash really fast.

When they do, they start looking for ways to get out of debt.

Enter these companies who buy annuities.

They’re experts at buying annuities for pennies on the dollar. They might come in and offer someone $150,000 for the annuity that’s paying $25,000 a year. This might look like a godsend to someone who’s in over their head with debts because of lifestyle changes.

But for the company buying the annuity, the return on investment is huge. They’ll have paid off the $150,000 in 6 years with the money from the annuity. The rest of the money is pure profit.
Some companies even buy and sell annuities to each other at a profit.

What is hit frequency?

Hit frequency refers to how often a slot machine hits a winning combination. The concept is related to the house edge and the payback percentage, but it’s not the same thing.

A slot machine that hits often but only for small wins might have a lower payback percentage than a slot machine that hits only seldom but has higher average wins.

Slot machine designers and manufacturers have enormous amounts of data informing their decisions about hit frequency and payback percentages. They know what hit frequency combined with what payback percentage will maximize a player’s time spent on machine, which is the #1 factor determining how profitable a particular game is.

Here’s the interesting thing about hit frequency. Human and animal psychology are set up in such a way that intermittent rewards are more powerful motivators than consistent rewards. We know this because of experiments conducted by BF Skinner.

He set up boxes which released food when a lever was pulled. The pigeons were motivated by the food to pull the lever.

But he found that pigeons were MORE motivated to pull the lever when they only got food some of the time. You would think that they’d be more motivated if they got a reward every time, but that’s not the case.

Slot machines are a perfect example of that theory in action.

How do wild symbols work?

A wild symbol on a slot machine works just like a wild card in a game of poker. It replaces and stands in for a symbol you don’t have that you need in order to create a winning combination.

Here’s an example:

You’re playing Ghost Rider slots from Playtech. The Ghost Rider symbol is wild. You get 4 of the same symbol on a payline, and the other symbol on that payline is Ghost Rider.

You get paid off as if you had 5 of that symbol on that payline.

Some wild symbols stack on top of one another, increasing the amount you’re getting paid off.

How do scatter symbols work?

Scatter symbols are slot machine symbols that create payoffs regardless of what payline they’re on. If you have a certain number of those symbols anywhere on the screen, you get paid.

Scatter symbols are a common feature on modern video slots. In some games, like the new 243 ways slots, every symbol in the game can be considered a scatter symbol.

What are bonus games and how do they work?

Bonus games are games that are triggered by the appearance of certain symbols on the reels. During these bonus games, you get to win additional prizes. On some games, the bonus might just be a random number of free spins. But on other games, you might get to spin a prize wheel or choose from a number of symbols which have prizes behind them.

How do progressive jackpots work?

A progressive jackpot game has a large jackpot with long odds of being hit. What makes it “progressive” is that it grows larger as the game is played. The casino and the machine take a tiny percentage of each bet to “fuel” the growing jackpot.

You can find multiple types of progressives. Some standalone games have a progressive jackpot that only increases when that individual machine is played. Some games are networked inside a particular consider, and their jackpot is tied into each of those games. When anyone spins the wheel on any of those games, the jackpot grows.

The biggest jackpots are found on the wide area progressive jackpots. These are games that are networked across multiple casinos. Megabucks is the most famous example, and the size of the jackpot on that game starts off at $10 million. It’s gotten as high as $39.7 million in the past.

What’s the difference between video slots and mechanical slots?

Video slots are the default kind of slot machine game now. They feature spinning reels, but they’re just animated reels on a computer monitor.

Mechanical slots have actual springs and gears controlling the spinning of the reels.

Even slots with mechanical-looking reels use a computer program (a random number generator) to determine their outcome these days.

What’s the difference between video poker and slot machines?

Video poker games look and act a lot like slot machines, but the differences are huge.

Slot machines are the only games in the casino where you don’t know the house edge. That’s because, even though you know the payoffs or the various combinations, you don’t know the odds of hitting that combination.

Video poker games use poker hands for their combinations, and the odds of getting a poker hand are known. If you know the odds of winning and the payoff for winning, you can calculate the house edge for the game.

The other major difference is that you make decisions on every video poker hand. You have the option to keep or discard any combination of cards that you’re dealt. This adds a skill element to video poker that is lacking in slot machines.

The final difference is that the payback percentage on video poker is almost always much better than the payback percentage on slot machines. Slot machines tend to top out around 95% with their payback percentages. That’s about where most video poker games start.

Are slot machines really streaky, cold, and/or hot?

Yes, slot machines are streaky. And they do get hot and/or cold.

But that’s not as good a bit of news as you were hoping.

The reason is that you have no way of predicting whether or not a slot machine will stay hot or cold for any length of time. These patterns that emerge during a gambling session or over the life of a gambling game are visible only in retrospect.

That’s because they’re illusory. During any series of random events, things are going to happen from time to time that look like streaks of good luck or bad luck.

That’s just the nature of random events, though. It’s not based on anything.

You’re no more or less likely to win on a slot machine if it’s paid off 10 times in a row than if it hadn’t paid off 10 times in a row.

Each spin of the reels is an independent event.

In that sense, no they’re not streaky. No, they don’t get hot or cold.

There’s a mathematical term for this flaw in logic. It’s called the gambler’s fallacy. It’s the assumption that the odds on your next trial change based on what happened on previous trials.

What is a loose slot machine? What is a tight slot machine?

“Loose” and “tight” are adjectives used to describe how often and how much a slot machine pays out. A loose slot machine usually pays off often and also has relatively large payouts. A tight slot machine, on the other hand, probably has a low hit frequency and relatively low payouts.

These are relative terms that don’t really mean much. They’re only meaningful in terms of comparing one machine to another. For example, there’s meaning when you say that the slots in the casinos on the Vegas Strip are looser than the slots at the airport. But there’s no real meaning when you say that a particular machine is tight.

Games are only loose or tight in comparison with each other.

What is a payback percentage? What about return to player? How do those numbers relate to the house edge?

The payback percentage is a calculation of how much the machine expects to pay back to the player over time. For example, if a game has a 95% payback percentage, over the long run, it should pay back 95% of the money fed into it in winnings. The other 5% is the house edge, and that’s how much the casino expects to win over the long run.

Here’s the thing, though:

The payback percentage is a long-term number. It makes sense in the context of tens of thousands of spins. It takes a long time, sometimes a lifetime, before a gambler begins to get into the long run.

And in the short run, anything can happen.

The average slots player makes 600 spins per hour. If you assume that the long run STARTS to come into play at 20,000 spins—which is just an assumption we’re making as an illustration—then it would take 33 or 34 hours to start getting into the long run.

Most players probably don’t spend that much time playing slots during a particular trip.

But if you know how much time is spent playing, you can calculate a player’s expected loss. You just multiply the spins per hour by the cost per spin and then by the house edge.


Let’s say you spend 40 hours playing dollar slots on a machine with a 95% payback percentage.

You’ll probably make 24,000 spins at a dollar a spin. That’s $24,000 you put into action. The machine should pay out, over time, 95% of that in winnings. That’s $22,800. Your expected loss is $1200.

The return to player is the same thing as the payback percentage. It’s just a different phrase that describes the same concept.

The house edge is just the payback percentage subtracted from 100%. That’s the amount the house expects to win over time.

And of course, in the short run, these figures are largely irrelevant. You might win big or lose really fast. Who knows?

Are slot machines rigged?

In a sense, yes, slot machines are rigged. But not in the way that you think.

All casino games are rigged, mathematically. That doesn’t mean the house has control over any individual result or playing session. It just means that over time the payoff odds on the bets are lower than the odds of winning. That creates a mathematical edge for the casino.

But slots don’t base their results on what’s happened previously. They’re not rigged in that way.

If you have a 1 in 1000 chance of hitting a jackpot on a slot machine, and you win, the odds of winning that jackpot again on the next spin remain the same—1 in 1000. They don’t go up or down based on what kind of playing session you’ve been having.

The casinos have no need to rig their games in any other way, because the math will pay off in the long run.

Are online slot machines legal?

Online slot machines might be legal or illegal depending on where you live. In the United States, it’s illegal at the federal level to bet on sports. It’s illegal to run an online casino without proper licensure. But it’s not, strictly speaking, specifically illegal to play a slot machine for real money on the Internet.

But individual states have their own laws. Some of them have legalized and regulated online casinos—Nevada and New Jersey are 2 examples. In those states, it’s legal to play, but only at the correct casinos.
Other states have specific laws related to online gambling. In those states, it’s flat-out illegal to play specific games, but maybe not others. The worst example we can think of is the state of Washington, where it’s a felony to play poker online for real money.

Then there are more enlightened countries like the United Kingdom, where you can play at regulated casinos as much as you want to.


The number of questions asked about slot machines is probably only limited by the number of gamblers who play slots. We’ve tried to answer the most frequently asked questions on this page. If you can think of questions we can answer on this page to make it a more comprehensive slot machines FAQ, please contact us and let us know. We’ll expand the page accordingly.