How Do Slot Machines Work? Slot machines come in various shapes and sizes, and are, by far, the most popular form of casino games not only in Michigan and the rest of the US, but the world. Many also consider slots to be the simplest of all casino games and a perfect way to start your casino adventure. On a slot machine, a random number generator (RNG) picks a random number for each reel, which each number matching a stop on its reel. Then the machine directs the reels to stop on the spots selected by the RNG. Note that by the time the reels are spinning, the game is already over. Inside each machine is a computer that operates on a code or mathematical equation. This slot machine algorithm works as a random number generator, also known as an RNG. These numbers are constantly generated, and depending on the exact moment you click 'spin', you will get different results.
Introduction to How Slot Machines Work
In these series of posts, I continue to answer the most common questions about slot machines asked via Google searches. This post explains the simple question of how slot machines work.
In this post, I will discuss the operational components of a slot machine from the point-of-view of a slots player. Meaning, the various interface areas on the front of a slot machine. These player interface areas include:
- Service Light
- Bonus Display (Optional)
- Pay Table
- Players Club
- Results
- Play Console
- Ticket In, Ticket Out (TITO)
Additional relatively minor interface areas are not listed or shown below. These areas are the locations audio speakers, audio volume control (optional), display lights, lever arm, and a hearing aid jack to accommodate those with a hearing disability.
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Service Light
A slot machine's service light is generally located at the very top of a slot machine to be easily visible to casino employees. Because of this uppermost location, it's also known as the candle within slots terminology.
Slots players can switch on the service light by activating the service button on the player console. Or, it will enable by itself if the player wins a hand pay jackpot or the slot machine develops a service fault. Faults might include lack of paper, a full cash-in condition, mechanical or electronic tampering, or an internal electronic failure such as CPU overheating, etc.
Modern casinos have a slot attendant call/dispatcher communication system using a headset and microphone. This setup is helpful for spotting problems on the casino floor. An activated service light automatically notifies the casino operating system. The casino dispatcher then informs the slot attendant responsible for that section of the casino.
Once the notification is sent out, a lit candle is of little practical use. At best, it guides the responding slot attendant the last few feet to the customer needing attention and, also, provides some reassurance to the waiting customer.
Slots players may activate the candle for a multitude of reasons. In general, they do so to deliberately call a slot attendant to their location, for any of a host of reasons only limited by imagination.
Pro-Tip #1: Service Light
Sometimes slots players need to leave a slot machine briefly but don't want to give it up to someone else. If this break is relatively brief, say 10-15 minutes, use the service button to call over a slot attendant. The slot attendant can temporarily lock up the slot machine at the request of the player.
The slot machine can be unlocked later by the player via insertion of only their service card … or after 10-15 minutes when the temporary lockout automatically expires. For the specific length of lockout times, ask any slot attendant at your casino.
Bonus Display Area
If a specific slot machine has a bonus round available, then it will often have a second display area. Video slots may use the same primary display screen but abruptly display the bonus round game theme instead. However, video slots most often have a secondary display screen available for bonus rounds.
The Bonus Display area is optional and dependent upon the specific slot machine model. The location of this bonus display varies. More often than not, it is high up on the slot machine to be viewable by other players from a distance.
Regulations require a casino operator to sponsor junket applicants before licenses are issued to them to operate at that particular casino. Since lifting its long-standing ban on casino gambling in 2005, Singapore has established a stringent regulatory regime on the industry, including tough probity checks and licensing for junket operators. Singapore licensed two casino junket operators. AUSTRAC says that between April 2018 and the end of March 2019, 635 suspicious matter reports were submitted to the agency about junkets, with two unnamed casinos accounting for two-thirds of the. Singapore's casino regulator has issued its first-ever junket-operator licenses to two agents, in a move that hands one of the city-state's two casino resorts a coveted avenue to expand its. The Casino Regulatory Authority of Singapore (CRA) has awarded the first batch of junket licenses to two Malaysian operators on Thursday.
Casinos offset their losses by offering slot machines with bonus round display visible from a distance. Frankly, wins on these highly visible and usually loud bonus displays are seen by many. This obvious win encourages other casino patrons to play slot machines.
Pro-Tip #2: Bonus Round
Bonus rounds generally cannot be activated unless that slot machine's maximum credits are bet. By not betting maximum credits, the player automatically lowers their odds of winning.
If betting maximum credits on a specific denomination slot machine is not affordable, pick another affordable slot machine. I discuss this approach in detail at Choosing Slot Machines.
Pay Table Area
The Pay Table area lists information on the jackpot amounts for specific reel combinations. It can also display some or all of the game theme rules. This area may be permanently displayed on the slot machine, or possibly only available through an interactive series of images available by touchscreen.
In either case, all possible wins may or may not be displayed. Sometimes the list is highly abbreviated, and displays only the highest jackpots, due to space limitations. Other times, mainly with touchscreen displays, a series of images can be switched between to view every possible winning combination.
However, pay tables typically provide the highest value jackpot. Slot machine game themes with multipliers or 'wild' reel symbols have their most top value jackpots being the result of these reel symbols. Alternatively, it may not show all multipliers or 'wild' symbols in the tabulated list of win-reel combinations. Instead, they may be in writing along the edge of the paytable interface area.
But, with large touchscreens has come the capability to provide full paytable information along with game theme rules. Some slot machines now have this feature and, perhaps, more will have it in the future.
Many paytables show the number of credits that would be won for a specific combination of reel symbols. Or, they may show a monetary amount. In either case, these tables have separate columns for winning combinations dependent upon how many credits are bet. The far–right column typically shows the winning jackpots available when betting maximum credits.
Some examples of credit and denomination combinations are:
- 1-credit slot machines having a $100 denomination
- 3-credit slot machines having a $5 denomination
- 5-credit 'quarter slots' having a $0.25 denomination
- 300-credit 'penny slots' have a $0.01 denomination
Pro-Tip #3: Pay Tables
Frankly, learning the paytable of any slot machines played is a relatively easy way to improve the odds of winning at slots. Many typical slots players believe there is no skill involved in winning at slot machines. Casinos gently foster this misunderstanding, as it is to their benefit. Don't fall for it.
Traditionally, slots players find it acceptable to play slot machines with visual succinct paytables. Frankly, casinos would instead have their customers spend their time playing a game they don't understand.
The casino isn't making money if a player spends time studying or reading until they do understand rather than playing the machine.
One easy-to-learn skill to improve the odds of winning at slots is choosing which slots to play based on their paytables. I discuss this in detail at Choosing Slot Machines.
Players Club Area
The Players Club area contains a card reader, numbered keypad, and a small display. A security feature of players club cards is for players to choose a PIN to enter when they wish to access their player account.
Newer-style slot machines have a touchscreen display, which removes the need for a physical keypad. Meaning, it's part of the touchscreen display.
Bets can be made on a slot machine without a players' club card. At most casinos, it typically is not required. Neither is the PIN needed to play the device or view basic information. For example, a running total of reward points earned during the current play session is generally on display.
The PIN is required, however, to:
- access certain portions of player's casino account
- transfer banked funds
- activate 'free play' provided by the casino as a complimentary gift
Results Area
The Results interface area is where the reel combinations are seen after making a bet. Whether a video slot machine or a slot machine with physical reel, this is where the results of a bet are provided.
Interpreting whether a reel combination is a winner requires an understanding of the paytable. This result is fundamental to how slot machines work.
Of course, the slot machine will immediately display the results. A small display beneath the reels shows:
- the total amount of money or credits available in the machine
- how many credits most recently bet
- the jackpot amount won if any
Jackpots are usually in credits, where each credit equals the denomination of the machine rather than the amount bet, as well as a monetary amount.
Player Console
The Play Console typically has physical buttons, a cash/ticket reader, and a ticket printer. The buttons include:
- Cash Out for requesting the removal of any player funds in the machine
- Service to request a casino attendant
- A Series of Buttons for selecting the number of credits to bet, or placing the maximum possible bet
- Cash Out for removing any remaining bankroll
- Repeat to making another bet for the same credit(s)
- Denomination to select a specific bet denomination (optional)
The player console may have several possible button configurations, dependent upon the model of the slot machine. Given how often game themes are switched to maintain the interest of players over time, it is common for player consoles to be standardized over many machines within a casino.
Also, it is becoming common for consoles to have embedded displays visible through their semi-transparent button covers. This array of small screens are linked together to show visually stunning composite images displayed across the entire array of buttons.
Ticket In, Ticket Out (TITO)
By the beginning of the 21st Century, the use of coins was removed from casinos. This removal was for the sake of convenience of both the casino and customers. Both had issues with handling so many coins. Customers because of the difficulties inherent with carrying so much weight, but also gambling delays due to full (or empty) slot machine coin hoppers.
Casinos had issues with coins as well, including customer complaints due to delays caused by a full (or empty) slot machine coin hopper. This inconvenience was a coin logistics issue, which also included higher costs of maintaining a larger vault space and coin processing equipment and services. As casinos became more popular, coins became more difficult for everyone.
As a result, Ticket-In, Ticket-Out technology was pulled into casinos. They are now integral to how slot machines work. This automation is the same technology that was beginning to be seen in Automated Teller Machines (ATMs). Once proven out, this slot machine technology was here to stay like so many others.
Summary of How Slot Machines Work
I've discussed the operational components of a slot machine from the point-of-view of a slots player. This explanation of how slot machines work included the various player interface areas on the front of a typical slot machine.
There are additional relatively minor interface areas. These areas include audio speakers, audio volume control (optional), display lights, lever arm, and a hearing aid jack to accommodate those with a hearing disability.
Related Articles from Professor Slots
Other Articles from Professor Slots
- Previous: Where Were Slot Machines Invented Historically?
- Next: Why Do Slot Machines Say Bar on Their Reels?
Have fun, be safe, and make good choices!
By Jon H. Friedl, Jr. Ph.D., President
Jon Friedl, LLC
I don't often recommend playing slot machines to new casino gamblers, but I'm also aware that some people are going to gamble on the one-armed bandits regardless of my suggestions.
And that's okay.
But if you ARE going to play slot machines, at least understand what you're getting into.
If you're a beginner, you should understand the answers to these seven important slot machine questions:
1 – How Do Slot Machines Actually Work?
Slot machines used to be mechanical games powered by levers, springs, and spinning reels.
Modern slot machines retain the lever and the spinning reels, but they're both just for show, mostly.
Today's real money slots use computer-generated random results and display the reels on the symbols just for show.
You probably want more details than that, though, right? You're probably even hoping for some math.
Here you go:
Random Number Generators
Each symbol on the virtual slot machine reels are programmed to come up a specific percentage of the time. This percentage is the weighting for that symbol. If you have 10 symbols, some of them might be programmed to come up 1/5 of the time, while others might be programmed to only come up 1/20 of the time. The rest might be programmed to come up 1/10 of the time.
The computer program generating these results is called a random number generator (RNG). Such a program is constantly cycling through numbers – thousands of numbers per second. Each of those numbers corresponds to the probability of a symbol coming up.
When you pull the lever or hit the spin button on a slot machine, the computer program instantaneously stops on whatever number it was thinking of in that instant.
In fact, the slot machine game knows the outcome before the reels even stop spinning.
This is close enough to random for anyone except the most bizarre theoretical purist.
Also, each spin of the reels is an independent random event. This means that the combinations don't cycle through on any kind of predictable basis. (Remember, the computer is running through thousands of numbers per second.)
The payouts for the various symbol combinations all have one thing in common:
They pay out at a much lower rate than the odds of getting that combination would warrant.
The total payouts for the machine are always lower than even when compared to what would happen if you hit every possible combination in some theoretically perfect set of slot machine spins.
Examples of Payback Percentages
You might have a combination of three cherries that pays out at 1 for 1 odds – this means you basically have a push situation. You win back what you spent when you made the spin, but you don't make any profit.
If that combination came up 100% of the time, you'd be playing a game where you'd break even forever. You couldn't win or lose.
But a more common probability of hitting that combination might be 20%.
And if you're winning 1 unit 20% of the time, you're looking at a 20% return for that combination.
If that were the only winning combination in the game, the game would have a total payback percentage of 20%. The house edge would be 80%.
That's because they have more winning combinations than that, and in varying amounts.
For example, you might have a 2nd combination of symbols –three plums maybe—that pay off at 2 for 1 odds. The probability of getting that combination might be 10%, which would add 20% more to the payback percentage for the game, giving it a 40% payback percentage total.
To get the payback percentage, you multiply the amount you'd win by the probability of winning. Then you add every possible combination to get an overall percentage.
And that's how modern slot machine math works.
2 – Are Slot Machines Rigged?
Does this mean slot machines are rigged?
Only in a vague sense.
Most people who think slot machines are rigged think that the casino controls when a slot machine pays out so that they can accomplish something nefarious.
For example, they think that a slot machine that just paid out won't pay out again for a while so that the game can 'catch up' to its expected payback percentage.
Sorry, that's just not how the games work.
The casinos don't need to cheat, slots are just a lousy bet.
In some casinos, the payback percentage for a slot machine might be as low as 75% or less. A lot of the slots at the airport in Vegas have such low payback percentages.
If you're playing in a local bar in a state where slot machines are illegal, you can probably expect the payback percentage to be over lower. I don't have any official numbers, but the 8-liners that skirt the law in Texas probably have a payback percentage no greater than 60%.
At legit casinos, though, you're looking at payback percentages between 75% and 95%.
3 – How Do You Trick a Slot Machine?
You probably think I'm going to be like most gambling bloggers and say that it's impossible to trick a slot machine.
That's not true, though – you can trick a slot machine.
Just ask Tommy Glenn Carmichael. I'm sure he'll be happy to explain multiple ways he's tricked slot machines over the years. He's one of the most legendary casino cheaters in the world.
He's far from the average gambler – for the average gambler, trying to trick a slot machine is an exercise in futility and silliness.
One tool that Tommy used to trick slot machines into paying out was called the Monkey's Paw. It was a wire device he stuck in the payout chute to press the switch that triggered a payout. Such a device would be obsolete today, but it's just an example.
Don't even try to cheat at slot machines, though – you'll spend time in prison if you get caught.
And you might not get caught your first time, but you won't be able to stop once you start, so you'll have to keep avoiding detection.
It's a lousy bet. You won't get to keep the money, and you'll spend time in prison.
That's not a fair trade at all.
4 – Are There Secrets to Winning on Slot Machines?
No, there are no secrets to winning on slot machines.
I went to a casino in Oklahoma with a lady friend of mine once. She told me her 'secret strategy' for winning on slot machines. She said that she always plays the exact same machine.
She thought that would improve her odds eventually of hitting.
It's like the guy who sells the 'winning the lottery' system who claims he's won the lottery seven times. His big secret?
Buy lots of lottery tickets.
He reveals how much money he's won, but he never reveals how much he spent on the lottery tickets to win that amount.
I'd be willing to get my pickup truck that he's operating at a serious loss.
So, no – the only secret to winning at slot machines is to keep spinning the reels.
5 – How Do Progressive Slots Work?
Progressive slots are the slot machine games with the jackpot tickers on top that show an ever-increasing jackpot.
How can such games afford such large jackpots?
If the jackpots get large enough, won't the games eventually become a profitable proposition for the slot machine player?
First question answered first – such games can afford such large jackpots because they take a tiny percentage from each spin to fuel that jackpot. It might be as low as 0.5% or 1%, but it counts against the payback percentage from the game.
Second question answered – yes, if the jackpot gets big enough, the game becomes a positive expectation bet.
But that's not a practical reason to play it. If the odds are 1 in 10 million of hitting the progressive jackpot, you'll have to play for 20,000 hours to hit that jackpot (on average).
That's the equivalent of working a full-time job for 10 years straight. By that time, someone else will have hit the jackpot, and it will have gone back to its original value – which is NOT a positive expectation bet.
Also, it's impossible for you to know when the jackpot has gotten high enough because you don't know what the probability of hitting the various jackpots and other prizes on the game are.
Real Working Slot Machines For Sale
Slot machines are essentially opaque – you don't know what probabilities the symbol combinations have programmed to them.
6 – How Do You Find Loose Slot Machines?
Ignore all the well-intentioned advice on the internet about how slot machine managers place the loosest machines in specific locations in the casinos to try to lure gamblers to play the slots. This advice is universally lousy.
There are additional relatively minor interface areas. These areas include audio speakers, audio volume control (optional), display lights, lever arm, and a hearing aid jack to accommodate those with a hearing disability.
Related Articles from Professor Slots
Other Articles from Professor Slots
- Previous: Where Were Slot Machines Invented Historically?
- Next: Why Do Slot Machines Say Bar on Their Reels?
Have fun, be safe, and make good choices!
By Jon H. Friedl, Jr. Ph.D., President
Jon Friedl, LLC
I don't often recommend playing slot machines to new casino gamblers, but I'm also aware that some people are going to gamble on the one-armed bandits regardless of my suggestions.
And that's okay.
But if you ARE going to play slot machines, at least understand what you're getting into.
If you're a beginner, you should understand the answers to these seven important slot machine questions:
1 – How Do Slot Machines Actually Work?
Slot machines used to be mechanical games powered by levers, springs, and spinning reels.
Modern slot machines retain the lever and the spinning reels, but they're both just for show, mostly.
Today's real money slots use computer-generated random results and display the reels on the symbols just for show.
You probably want more details than that, though, right? You're probably even hoping for some math.
Here you go:
Random Number Generators
Each symbol on the virtual slot machine reels are programmed to come up a specific percentage of the time. This percentage is the weighting for that symbol. If you have 10 symbols, some of them might be programmed to come up 1/5 of the time, while others might be programmed to only come up 1/20 of the time. The rest might be programmed to come up 1/10 of the time.
The computer program generating these results is called a random number generator (RNG). Such a program is constantly cycling through numbers – thousands of numbers per second. Each of those numbers corresponds to the probability of a symbol coming up.
When you pull the lever or hit the spin button on a slot machine, the computer program instantaneously stops on whatever number it was thinking of in that instant.
In fact, the slot machine game knows the outcome before the reels even stop spinning.
This is close enough to random for anyone except the most bizarre theoretical purist.
Also, each spin of the reels is an independent random event. This means that the combinations don't cycle through on any kind of predictable basis. (Remember, the computer is running through thousands of numbers per second.)
The payouts for the various symbol combinations all have one thing in common:
They pay out at a much lower rate than the odds of getting that combination would warrant.
The total payouts for the machine are always lower than even when compared to what would happen if you hit every possible combination in some theoretically perfect set of slot machine spins.
Examples of Payback Percentages
You might have a combination of three cherries that pays out at 1 for 1 odds – this means you basically have a push situation. You win back what you spent when you made the spin, but you don't make any profit.
If that combination came up 100% of the time, you'd be playing a game where you'd break even forever. You couldn't win or lose.
But a more common probability of hitting that combination might be 20%.
And if you're winning 1 unit 20% of the time, you're looking at a 20% return for that combination.
If that were the only winning combination in the game, the game would have a total payback percentage of 20%. The house edge would be 80%.
That's because they have more winning combinations than that, and in varying amounts.
For example, you might have a 2nd combination of symbols –three plums maybe—that pay off at 2 for 1 odds. The probability of getting that combination might be 10%, which would add 20% more to the payback percentage for the game, giving it a 40% payback percentage total.
To get the payback percentage, you multiply the amount you'd win by the probability of winning. Then you add every possible combination to get an overall percentage.
And that's how modern slot machine math works.
2 – Are Slot Machines Rigged?
Does this mean slot machines are rigged?
Only in a vague sense.
Most people who think slot machines are rigged think that the casino controls when a slot machine pays out so that they can accomplish something nefarious.
For example, they think that a slot machine that just paid out won't pay out again for a while so that the game can 'catch up' to its expected payback percentage.
Sorry, that's just not how the games work.
The casinos don't need to cheat, slots are just a lousy bet.
In some casinos, the payback percentage for a slot machine might be as low as 75% or less. A lot of the slots at the airport in Vegas have such low payback percentages.
If you're playing in a local bar in a state where slot machines are illegal, you can probably expect the payback percentage to be over lower. I don't have any official numbers, but the 8-liners that skirt the law in Texas probably have a payback percentage no greater than 60%.
At legit casinos, though, you're looking at payback percentages between 75% and 95%.
3 – How Do You Trick a Slot Machine?
You probably think I'm going to be like most gambling bloggers and say that it's impossible to trick a slot machine.
That's not true, though – you can trick a slot machine.
Just ask Tommy Glenn Carmichael. I'm sure he'll be happy to explain multiple ways he's tricked slot machines over the years. He's one of the most legendary casino cheaters in the world.
He's far from the average gambler – for the average gambler, trying to trick a slot machine is an exercise in futility and silliness.
One tool that Tommy used to trick slot machines into paying out was called the Monkey's Paw. It was a wire device he stuck in the payout chute to press the switch that triggered a payout. Such a device would be obsolete today, but it's just an example.
Don't even try to cheat at slot machines, though – you'll spend time in prison if you get caught.
And you might not get caught your first time, but you won't be able to stop once you start, so you'll have to keep avoiding detection.
It's a lousy bet. You won't get to keep the money, and you'll spend time in prison.
That's not a fair trade at all.
4 – Are There Secrets to Winning on Slot Machines?
No, there are no secrets to winning on slot machines.
I went to a casino in Oklahoma with a lady friend of mine once. She told me her 'secret strategy' for winning on slot machines. She said that she always plays the exact same machine.
She thought that would improve her odds eventually of hitting.
It's like the guy who sells the 'winning the lottery' system who claims he's won the lottery seven times. His big secret?
Buy lots of lottery tickets.
He reveals how much money he's won, but he never reveals how much he spent on the lottery tickets to win that amount.
I'd be willing to get my pickup truck that he's operating at a serious loss.
So, no – the only secret to winning at slot machines is to keep spinning the reels.
5 – How Do Progressive Slots Work?
Progressive slots are the slot machine games with the jackpot tickers on top that show an ever-increasing jackpot.
How can such games afford such large jackpots?
If the jackpots get large enough, won't the games eventually become a profitable proposition for the slot machine player?
First question answered first – such games can afford such large jackpots because they take a tiny percentage from each spin to fuel that jackpot. It might be as low as 0.5% or 1%, but it counts against the payback percentage from the game.
Second question answered – yes, if the jackpot gets big enough, the game becomes a positive expectation bet.
But that's not a practical reason to play it. If the odds are 1 in 10 million of hitting the progressive jackpot, you'll have to play for 20,000 hours to hit that jackpot (on average).
That's the equivalent of working a full-time job for 10 years straight. By that time, someone else will have hit the jackpot, and it will have gone back to its original value – which is NOT a positive expectation bet.
Also, it's impossible for you to know when the jackpot has gotten high enough because you don't know what the probability of hitting the various jackpots and other prizes on the game are.
Real Working Slot Machines For Sale
Slot machines are essentially opaque – you don't know what probabilities the symbol combinations have programmed to them.
6 – How Do You Find Loose Slot Machines?
Ignore all the well-intentioned advice on the internet about how slot machine managers place the loosest machines in specific locations in the casinos to try to lure gamblers to play the slots. This advice is universally lousy.
The best thing you can do is follow some practical guidelines about how to choose slot machines that probably have a better payback percentage than others.
For example, avoiding progressive slots and playing games with a flat top prize is a good idea.
Playing games which have no special bonus features is also a good idea.
The more bells and whistles a slot machine game has, the worse the payback percentage tends to be.
Slot Machines For Sale
But forget all about the idea that some slot machines are loose or tight for various conditions and reasons.
That's just not how it works.
7 – Are Casino Slots Intelligent?
This question stems from the idea that a slot machine somehow knows what its payback percentage is supposed to be, and then, when it pays out a big jackpot, it adjusts by 'tightening up' until it catches up to that theoretical percentage.
Every spin of the reels is independent of the spin before it. If the probability of hitting the top jackpot on the machine is 1 in 4000, it's 1 in 4000 on every spin regardless of what happened on the previous spin.
If you hit a jackpot, then spin the reels again, the probability of hitting the jackpot again is still 1 in 4000.
How Do Slot Machines Work Reddit
Conclusion
Slot machines, generally, are a lousy bet. There's no skill element, and you really have no way of knowing how good or bad one slot machine is compared to the next one.
Working Slot Machines For Sale
In fact, you can have two identical slot machines sitting adjacent to each other, and they might have entirely different payback percentages based on their programming.
How Do Slot Machines Work In Vegas
But, if you're going to play slots, at least you're now educated on how they work and you have the answers to the most important slot machine questions.
