Slot machines are coin-based games that generate a variety of numbers and symbols in different patterns on the reels. Each combination can lead to winning various amounts of money, depending on the type of payline the player gambles on and bonus features available.
Over the years, slot machines have evolved and made their way into the online casino world. Since becoming a huge part of online gambling, casinos have created ways to ensure the fairness of the game for players themselves to be able to test. Provably fair slots are the new standard for casino games, but some are still audited by third-party companies.
Online slots have various risks ranging from the low-risk, casual play to the high-risk, high-reward gameplay. Players are able to choose their risk level based on various factors such as their betting strategy, max win potential, and other factors including the bonus structure of the game.
This article is going to give everything you need to know about slot games, from how to play them to the history to strategies. This is a one-stop shop for a slot game and is here to help players gain a broader understanding of the game itself.
Gameplay & Rules
The Goal
Playing slots can range in volatility and, in turn, change the way each player decides their type of playstyle. The ways to play can vary, but overall, it is very simple to understand. Players will log in to their desired online casino and start by depositing the amount they are comfortable with wagering. Different casinos offer different currencies, and there are deposit and withdrawal limits and regulations, so make sure to read about those in our other articles.
Once the deposit has been made, there are thousands of games to choose from. Whichever game the player chooses depends on the specifics of how to play—which we will discuss further down the line—but for now, the concept of slots is simple. There are 3+ reels with various symbols that players try to match in various paylines.
The paylines will then determine the player's payout amount, and the earnings are then put into their virtual wallet for them to later withdraw. Slots can vary, from placing bets on multiple paylines to no paylines at all. In the later sections, we will discuss in more detail what types of slots there are and how players use each one, but for now, let’s go on to the basics of every slot game.
Types of Slots
Classic Slots
If players are looking to play more nostalgic slot games, classic slots are the type to choose. Classic slots are the original type of slots that are simple and traditional. They are anything but complicated and are what the other slot types are based on.
While we discussed earlier how players are able to place bets on multiple paylines, classic slots are limited to just one: the single payline. Classic slots often only use 3 reels compared to the 5+ reels in modern-day slots.
The theme for these slots is very traditional and includes basic visuals and audio. The symbols are the iconic fruit, bells, bars, and stars from the original machines created. Along with the simple theme, the payout structure is just as easy. By matching the three across, players can instantly realize if they won or not and can have special combos like 7-7-7 or BAR-BAR-BAR.
Players enjoy the intentional old-school, nostalgic fonts and simple animations. Players are also drawn to the fact that classic slots do not usually include bonus features like free spins, bonus rounds, complex multipliers, or scatter pay. This creates low variance and reduces confusion for most players, making it easy to remember how to play. Due to the low variance and single payline in classic slots, the volatility of the game is also low and has little risk, making it another reason players gravitate toward this type of slot.
Video Slots
With the help of game advancement, video slots have become the most modern version of common slots and include 5 or more reels. Video slots are the most widely played in the gambling industry for both land-based and online casinos. Many players love video slots since they integrate more complex features and payout structures than classic slots.
Video slots have created a new way for gamblers to play. Video slots have rich graphics and themes associated with them and can engage players on an emotional level. By using advancements in technology, players are able to choose from slots designed like mini video games. The themes are what appeal to the players and can be the reason for choosing a specific game.
While there are some amazing themes for video slots, there are also complex payout structures. Video slots are drastically different since they use multiple paylines and sometimes hundreds of options. Another option they can choose in video slots is using no paylines at all but Megaways. Megaways use the symbols by matching them across a grid in no specific pattern but by the number of matching symbols total. This creates thousands of ways for players to win and can be very exciting when played with the themes and bonus features.
Bonus features are one of the most enticing factors for some players when it comes to video slots. This makes the game more interactive for players, and each game can include multiple features. Popular features include free spins, prize-picking mini games, bonus wheels to spin for multipliers and jackpots, as well as bonus buys that players can purchase. All of these features can change the volatility of the game and rely on RNG heavier than other types of slots.
Since video slots are completely digital, the outcomes still need to be digital. The randomness is controlled completely by the RNG, reel strips, and weights on the symbols. By eliminating the mechanical limits of the game, it allows for larger jackpots, more customization in the features, and more control over the risk involved.
Progressive Jackpot Slots
Progressive jackpot slots are exactly what they sound like; this is a type of slot where a player places a bet and, when they lose, part of their bet gets placed into a jackpot or pool. The total of this gets added together to create a chance for players to win big. The jackpot will continue to gradually grow until one lucky person spins and wins.
There are various types of progressive jackpot slots, such as the standalone progressive, in-house progressive, and wide-area network progressive. Each of these varies in how large the prize pool can get, but let’s talk about what each one means.
In a standalone progressive, the name says it all. This is where the jackpot will grow on a singular machine in the same casino. In turn, it makes this type easier to win than the others. The only downside to playing this progressive is the jackpots are usually smaller since they are easier to obtain.
In-house or local progressives contain a jackpot that grows through multiple connected machines within the same casino. These progressives are a bit harder to win than the standalone, but having multiple machines involved makes the jackpot grow even quicker and larger.
Lastly, there is the wide-area network progressive. This works by having multiple machines across many casinos grow a singular jackpot. Winning these jackpots can be life-changing for players since they can grow to millions of dollars. This makes winning these jackpots extremely rare, and the wins can be spread months apart from each other.
There are many factors that can trigger wins in progressive jackpots. Three triggers would be landing on a specific combination of symbols, winning a bonus game, or just purely random chance. Since you are betting on the chance to win large amounts, the volatility for this type of slot is very high and can be considered a small-scale lottery to some.
Megaways
This special feature is anything but basic and traditional. The company Big Time Gaming (BTG) created this feature for online slots in 2016. It became more popular when they later released the game Bonanza, which wasn't the first game to have Megaways gameplay but was and still is one of the most known.
Megaways created the most ways for players to win in slots and is now one of the most common ways to play slots in crypto casinos. This feature does not use traditional paylines but instead counts the number of times the symbol is shown on the reels to determine the payout.
In Bonanza, each symbol varies in rareness, so the payout for each one is different. It works by having 8 or more of the symbols on the screen and is, in a sense, similar to the game Keno, where you need to have multiple in order to start winning anything. The more matching symbols there are, the higher the payout for the spin.
Game Interface & Controls
How to Make a Bet
Step 1: In the settings of each game, players are able to choose their bet amount and the amount of paylines they are wanting to bet on. Some variations include betting a certain amount and winning based on how many symbols are matched across the entire screen, requiring no paylines.
Step 2: If you are wanting to do a manual play, then you just initiate the round by hitting the spin button. If you want to choose auto-bet, then you click the drop-down menu and fill out that section and then hit the spin button.
Step 3: The game will then either determine your winnings based on the payline you choose or by the amount of matching symbols on the screen.
Types of Bets
Standard Bet
We will later discuss the customizations and bonus features, but first, let's understand the base of the game. Standard bets are the default bets that a player can place. It is required for any slot game and is what starts your journey. In standard bets, it is plain and simple, where a player places their wager with no activated special features or modifications.
This includes the bet size you desire, standard paylines, and other natural features. In a standard bet, players just spin, and no extra risks are taken. Because of this, standard bets are considered to have low variance and a more fair return to player (RTP). Many players enjoy this style because it offers consistency and stretches their bankroll to play longer instead of short, quick plays.
Auto-Bet
This feature is in many crypto casino games and offers a faster way to play. There are many features and settings within auto-bet that can help players customize their experience. The main feature of any auto-bet is choosing the number of spins you want the game to do automatically for you in a row. This can be a good feature for a quick playstyle, and players are also able to add turbo spin.
Turbo spins affect the speed of the game, so if you don't really care to sit and watch the game at normal speed and just want even more instant results, this is perfect. Both of these features in auto-bet can also be bad if you do not manage your bankroll properly and can eventually wipe your bankroll out entirely.
Auto-bet also includes safety features that a player can put in place to help them better manage their bankroll and set strict limits to their gameplay. The features of stop on win and stop on loss are essential when using auto-bet. This helps players set the amount that they want to stop at, whether they are losing or winning. This can be beneficial for players because it helps them gain a sense of control and encourages safe gameplay.
Ante Bet
This is very similar to the bonus buy and often gets confused, but there are many differences between each. The Ante Bet or Bonus Bet feature allows players a chance at winning a bonus within their usual gameplay and spins. This is different from bonus buys since there is no guarantee of getting a bonus but just makes it more likely.
Since it is not a guarantee for bonuses, Ante Bet does not increase your base bet amount as steeply as bonus buys but instead increases it by 20x–50x. This feature helps to add more scatter symbols on the reels and moderately increases the volatility of the game. This feature caters more toward casual players that want to spice up their gameplay but isn't super high risk and doesn't take a big hit to their bankroll.
Multiline Bets
Multiline bets are very simple and straightforward but are more complex than simple single-line bets. As you can tell by the name itself, multiline bets let you place bets on multiple paylines in one spin.
The paylines are the patterns you choose for the symbols on the reels and can come in many different shapes. So instead of just betting straight across, you can choose various shapes like a V-shape or zig-zag. In multiline bets, players can choose to place bets on many shapes to help ensure higher chances of winning.
Bonus Buy Features
Bonus buy features are offered in many crypto casino slots; however, they are not allowed in most land-based casinos. This feature allows players to buy the bonus rounds instead of waiting for them naturally. Bonus rounds offer bigger wins and can be considered the most exciting section of the game for players. This can be a downside for players that enjoy more low variance, as it increases the volatility tremendously.
Buying the bonus rounds instead of waiting for them helps players jump and skip over the missed/dead spins and get straight to the higher risk with higher rewards. To buy this, there is usually a button on the side, and it tells you the price before purchasing. The price varies but is usually 50x–100x, sometimes more, of your initial base wager. The game will then immediately take you into the feature, which results in bonuses like free spins and multipliers.
Fairness & RTP
What is "Provably Fair"?
Provably fair slots were created to help players know that there is verifiable math that can guarantee the game did not cheat you. Many online casinos have a fairness tab in their navigation bar that can let players run tests based on the games being played to help players determine the fairness. It also explains how all the factors, such as the RNG and seeds, play a role in the game. That is not to say that the house edge and RTP don't play a factor. It is best to keep in mind that the house will always win in the long run.
Slots online can be provably fair through cryptographic measures. This means that each spin includes a complex process to generate multiple random values independently. There are measures that the game providers take to ensure high-quality slots, and you as a player are able to verify this through multiple factors.
To understand better, let’s go over how seeds play a role in all of this. There are two seeds: one being the seed randomly generated from an RNG through the casino that is kept a secret until after you bet, and then there is the client seed, which is unknown to the casino. There is also a nonce, which increases each spin by one, letting the game know it is a new spin and creating another randomized seed for the next game. These are all combined to then tell the machine to convert into reel stops and symbol combinations.
Each reel on the slot needs a random value, so there are multiple for each spin, creating a stream. This stream is produced by the seeds and nonce and becomes chunked together to ensure the game is verifiably random. All of this determines where the reels are stopped but does not determine the payout structure. In short, the RNG will select where to stop and show the player the corresponding symbol.
Key Stats
Online slot games vary in RTP but generally are around 96.0%–99.0% and have a very low house edge because of this. While it is still low, there is no way to beat the house edge and it is best to manage your bankroll accordingly. The odds of winning depend on the volatility a player chooses. If the player chooses a low-volatility slot, the chance of any payout is 25–40% and goes down even more while the volatility rises in risk. It is important to note that many wins are small, and a win does not mean there is any profit.
Betting Strategies
Since slots are a by-chance game, these strategies are more about how to play smarter than actually ways to beat the game. In this section, we will go over three main ways to improve your experience and reduce the loss, and while they are good to follow, they cannot guarantee any wins.
Strategy 1: Bankroll Management
Managing your bankroll has to be the most important strategy in any online casino game. There are many ways to make sure you do not wipe out your entire bankroll. Ways include not chasing losses (such as negative progression strategies), knowing your limits, and knowing when to stop.
Strategy 2: Percentage Betting
Percentage betting can help with your bankroll management. Percentage betting is when you adjust your bet amount as a set percentage of your total bankroll. Setting the percentage to around 1–3% can help reduce losses, but your wins can grow slower.
Strategy 3: Positive Progressive
It is best with any progressive betting system to use caution since there are limits set by the casino. Positive progression includes increasing your bet after a win and decreasing after a loss. By doing this, it lets you press winnings and is far less dangerous than negative progression systems that chase losses.
Terminology
Reels
Every slot game consists of reels in the gameplay. Reels are the columns displayed in the game that spin and hold the symbols. The reels can be mechanical, where they spin inside the machine; however, the most common are digital reels. Digital reels are displayed on a screen and can be in both land-based or online casinos. Digital reels have multiple mechanics such as cascading or tumbling effects that engage the player.
The number of reels displayed depends on the type of slot you play. Classic slot games only include 3 reels, whereas the more modernized slots can have 5 or more. The more reels displayed, the more advanced the gameplay can get in terms of complexity of the paylines and features included in the game.
Reels contain what is called a reel strip, which is a sequence of symbols that wrap around the reel and repeat. Each reel has a set number of stop positions. While it looks like the reels are actually spinning, the RNG has already chosen where the reels' stop positions will be beforehand. It works by the RNG picking where to stop, and when the player hits "spin," the game animates it to show that predetermined result.
There are various types of reels that can be used. Types include mechanical, video, weighted, Megaways, and cluster slots. Each type of reel can determine the playstyle for the game and varies based on the type of slot you are playing. Mechanical reels are the old-school classic reels that are physical with printed-on symbols. The other type is video reels; this is where the reels are digital and have various types of symbols.
Those are the two main categories that feed into other types like weighted reels. Weighted reels are used to control jackpot odds and make some symbols appear less. There are also Megaways and cluster slots. Megaways don't use typical paylines but instead count the number of matching symbols per spin. Cluster slots, also known as reel-less slots, don’t use typical reels but instead use grids. This is still considered slots but uses clusters of symbols instead of paylines.
Paylines
Now that paylines have been talked about numerous times in this article already, let's get into what they actually are. Paylines are the lined pattern(s) that determine if a player has won. The number of paylines is determined by the player but also by the type of slot being played.
There are various types and patterns for paylines. For example, classic slots only include one payline, which is the single payline. Single paylines are the typical horizontal paylines where the player tries to match the same symbols across the middle of the three reels. Then there is the standard multiple-payline option that includes patterns that go diagonal, zig-zag, V-shaped, and sometimes can even be customized.
In many slot games, players are able to choose the number of paylines they want to bet on, which can be good and bad. The more paylines the player chooses, the more chances to win; however, it also raises the total wager on each spin, so it is best to manage your bankroll properly and to look into all factors before choosing and betting.
Paylines and reels are the most important contents in a slot machine. Paylines influence way more than what meets the eye. They can determine how often you win, how big the win can be, the volatility of the game, and how you strategize your gameplay.
Themes
While paylines and reels are considered the most important contents of slots, themes are the most crucial part of the slots’ design. Themes go beyond the artwork involved and can determine the symbols, bonuses, sounds, characters, and the mechanics of the gameplay.
Themes are the identity of the games, making them more memorable to players, and some even choose the game solely based on the theme. The visuals for themes include not only symbols but the background and characters and determine the animation style—whether that be 2-D or 3-D.
Audio is another part that defines themes by creating engaging sounds, background music, and voice lines for the characters. By doing this, players are more likely to enjoy a game that has “satisfying” audio and is just as important as the visuals themselves. By using those two factors, games create stories and settings of where the theme is placed. Some types include ancient civilization, classic casino, fantasy, and even games based on favorite TV shows, movies, and brands.
The theme is what can make or break an experience for a player and can be the determining factor for whether the game is popular or not. All three of these contents make up the slots and are important to understand how they individually play a role in a gambler's experience. Now that we understand this, let’s move on to the types of slots and how players can customize their experience even more.
Other General terms:
Variance/Volatility: Used to describe how large the swings are in wins or losses and the frequencies of them. For example, high volatility means big wins or losses that are less often, and low volatility is small wins or losses but are more frequent. Variance mathematically measures the volatility and risk.
RTP: Short for return to player and is the amount expected to be returned in the long run.
House Edge: An advantage built into the odds in favor of the casino.
History and Evolution
Slots have grown so much dating back to the late 1800s. The first appearance of a true slot machine began somewhere between 1894–1895. Charles Fey created what was to be considered the revolutionary first real slot machine. The Liberty Bell was created in San Francisco and included 3 reels, 5 symbols, and automatic payouts.
The creation of the Liberty Bell established the 3-reel standard, the concept of jackpots, and symbol-based wins for the concept of the slots we know today. Since the first slot machine was created, places such as saloons and bars integrated them as ways to pass time, gain money, and gamble. The name of the game went by many names in these times, such as “fruit machine” and “one-armed bandit.”
After some years, technology started advancing, and around 1963–1964, Bally’s Money Honey was created. This machine replaced many mechanical parts with electrical components. This was considered to be the first electromechanical slot and impacted the industry by allowing faster gameplay, creating more reliable machines, and helping operators gain larger profits.
Not soon after the electromechanical machine became known, slots changed drastically. The very first video slot was created by Fortune Coin in 1976 and began with a Sony TV screen as the display. This changed slot games forever. By creating this, it opened a new world of animation and themes within the games, as well as bonus rounds. This became the foundation for the slots we know today and was a huge turning point in the casino industry.
Slot machines have since then changed entirely. Going into the 1980s and 90s, innovations such as weighted reels, multiline slots, themed machines, and progressive jackpots were formed. Once technology advanced past that, the first online slot appeared in the mid to late 90s.
Companies such as Microgaming, with the help of Cryptologic, launched and started the expansion of slots into the first online casinos, and this rapidly evolved. This created many factors that separated online games from the land-based ones previously. By creating this, it gave the game no physical reel limits, lower operating costs (which in turn gives higher RTP), created space for thousands of games, and the ability to track behavior.
All of these innovations evolved into what players see today. In the late 2000s, Bitcoin and provably fair games emerged. This gave room for crypto casinos to come into the playing field, which in turn introduced provably fair systems by using cryptography. This was the first time players could verify the fairness of the games themselves with no need for regulators or trusting operators blindly.
Since then, from 2020 till now, slots have integrated AI enhancements to help in balancing the game, creating skill-based bonus rounds, and more. Today’s slots have emerged with more regulations on the game by setting tighter rules on RTP transparency, restrictions on “near-misses,” and ensuring the games involve responsible gambling tools. Slots today are all about math, game design, entertainment factors, and psychology, thus creating a better experience for players no matter where they choose to play.
Conclusion
At the end of the day, it is up to you as a player to decide your fate. Slots are very random and by-chance games and can be fun for many players. Depending on the volatility, players are able to win big and customize their experience. Online slots are one of the many provably fair games in online casinos, but just make sure to investigate the casino as well as the game provider themselves.
Slots are made for beginners or veterans and can be played casually or very risky. This can create an exciting environment for players. It is best, no matter where you are in your journey, to remember safe gambling and to always manage your bankroll.
FAQ
Are slot machines rigged or are they truly random?
Slot machines are random due to the built-in Random Number Generator (RNG). This ensures that the game is not altered and is spun randomly each time. Another way to know is through the site or app’s licensing for who tests the game's provably fair mechanics—or test it yourself.
Does volatility play a role in slots and what is it?
Volatility is how often a game pays out. For instance, high-volatility games tend to have big wins but occur less often, while low-volatility games tend to pay players more often but in small amounts.
Are online slot games safe?
While there is uncertainty about gambling online, online slots are safe due to the fact that casinos are licensed and have been tested by third-party companies. Doing research before playing is highly suggested to ensure a player's safety.