by Matt Bourie

When people hear the word, “casino” most will imagine those colorful slot machines, with their flashing lights, spinning wheels, and handles being pulled by players who are aiming to win the jackpot.

In U.S. casinos, the most popular game, by far, is the slot machine. And how much of a casino’s profits in the U.S. are generated by slot machines? Well, let’s take a look at the 12-month period from March 1, 2020 through February 28, 2021 to see how much of Nevada’s casinos profits came from slots.

The total amount won by the state’s casinos during that one-year period was $7,327,153 and of that amount, a total of $5,152,988 came from slot machines. So, 70.32% of the money won by casinos in Nevada came from slot machines!

What are the reasons for the popularity of slot machines?

Well, there are a couples of reasons. Number one would be the fact that they are simple to play. Pretty much every one knows how to play a slot machine: just put in your money, push the “spin” button, or pull the handle, and wait to see if you are rewarded with a lucky win.

This procedure is much simpler than having to sit down at a table game with other players and trying to make betting and playing decisions for games where you may not completely know the rules or strategies.

And, number two on our list of reasons for the popularity of slot machines is that they are relatively cheap to play. Actually, penny machines are now the most popular slot machine denomination.

Once again, going back to Nevada’s gaming statistics for the 12-month period shown above, we know that there were 94,588 slot machines in the state’s casinos. 45,459 of those machines were multi-denominational, and of the remaining 49,039 machines in the state, 39,080 of those machines, or almost 80%, were penny machines. So, for many casino gamblers, they can throw a $20 bill into a slot machine and have some fun for a while, rather than playing a table game where that $20 might only last for one hand.

Slots are also available online, and just like those in casinos that come in all shapes and sizes, online slots come with different themes, bonus features, and payouts. The common thing about almost all slot games is that they offer a chance to win big by just betting a small amount of money. With this, many people are researching tips and tricks on how to win at slots.

While there is no magical formula on how to win at slots, being educated and learning more about them can let you have more fun and, maybe, increase your chances of winning. Or, at least to help you lose less and get more “bang for your buck” with your gambling bankroll.

If you’re looking to learn more about slot machines and online slots, you’re in the right place. Today, we are giving you our ultimate guide to playing slots. Read on for more details!


What are Slot Machines and How Do They Work?

A slot machine is one of the games you can play in a casino, and it features spinning reels. These reels have symbols, which land randomly after playing a bet and pull the lever. If the same symbols line up, the player will win prizes based on which symbol falls on the pay line.

Ultimately, however, in the simplest terms possible, modern slot machines are simply computers that randomly pay out more money than they take in.

Slot machines have been around since the late 19th century, but they still continue to be popular even online. Originally, slot machines were mechanical devices that relied on springs and gears to be able to spin the reels. Today, modern slot machines use a computer program called a random number generator (RNG) to direct the machine’s symbols where they should land on the reels that are displayed on the face of the machine.

An RNG is a computer program that rotates through thousands of numbers every second. Once you hit the spin button, or pull the handle, the program will stop and choose a combination. It is this combination that then tells the machine where the symbols should appear on the reels.


Short History of Slots

It was in the 1890s when the first slot machine was created by Charles Fey, who was a mechanic based in San Francisco. In 1898, he created the Liberty Bell, which was installed in game saloons throughout his hometown. However, since gambling was illegal in California, he couldn’t patent the device. With this, many imitations of the first popular slot machine emerged.

The machine had one pay line, three reels with five different symbols on them, and it gave out 50 cents when three bells aligned. In the present time, modern online slots can have millions of winning combinations. With this, we can say that the gameplay and variety of slots have indeed transformed well.

In the early 1900s, slots continued to grow. More symbols and pay lines were added. In 1964, the very first electronic slot machine was introduced in Las Vegas, and it was called Money Honey.

After a decade, the first video slot was made. It featured a flat-screen with low-resolution imagery, which is far from the games we know today. These machines looked like poor imitations of mechanical slots, and they did not have sound effects or bonuses that would attract players to try them.

During those early times, there were no computers or smartphones yet, and people did not trust technology that much. Most players back then believed that these early games were engineered against them. It was not until the creation of video poker in 1979 that electronic slots finally became popular.

The Odyssey series of slot machines arrived in 1996, and since then, slots have continued to evolve. This slot machine had an oversized screen, high-quality animation, and bonus features. It was the first step towards the type of games that we see today.

In the present time, there are countless variations of slot machines both in land-based casinos and online casinos. These games come in different sizes, shapes, colors, and themes. They also have many bonus rounds that give people a chance to win more, attracting them to play longer.


Different Types of Slots

With the advancement of technology, you can find many different kinds of slot games today. It’s because software providers are constantly searching for new ways on how they can entertain players. This means that the choice of online slots has increased a lot in recent years. Here are some of the different types of slot games that you might encounter:

  • 3-Reel Slots

This type of slot game is based on the classic fruit machine games that are found in arcades in different parts of the world. These are the simplest form of online slot machines. They are very easy to understand.

There are three columns on a window with three rows of symbols. The center line is known as the main pay line, but the machine can easily have more pay lines, up to nine in total. The player will bet and then spin the reels. If the symbols on the pay line match a winning combination from the pay table, the player will win the equivalent amount of money for that combination.

slot machine with three reels

A three-reel slot machine

  • 5-Reel Slots

Five-reel slots are also called video slots. It is a more complex type of slot. Instead of having a single pay line, it can have up to 100, which gives players more chances of winning on each spin. Since it has extra reels and multiple pay lines, this type of slot game also has a more detailed paytable. In addition, there are also special features like wilds and scatter symbols, which can give players even more chances of winning.

  • 3D Slots

The rules, gameplay, and pay lines in 3D slots are exactly the same as 5-reel slots. The only difference is that it features an assortment of 3D animated characters that intermingle with the players during the game to trigger bonuses and other incentives. It gives the game a narrative-driven feel because each 3D slot offers various settings and storylines. Its visual and audio effects combined with different themes give players a unique experience.

  • i-slots

This type of slot game is also interactive, but it allows players to create their own storyline by taking part in an adventure. To advance the game, the player needs to spin different combinations of reels. Each result provides different ways to finish the game and the storyline.

  • Feature Slots

These slot machines have special features, including bonus rounds and extra spins. These bonuses are unlocked via Wilds and Scatters. They are random symbols that act as wildcards, giving players more chances to win on every spin.


Basic Features of Slot Games

Slot games are easy to play, and they can lead to hours of fun. However, before you start, it is essential to understand first how you should approach the games. This is important if you want to maximize your chances of winning aside from enjoying the games. As mentioned earlier, slots come in different types. But here are some of the basic features that you will find on almost all slot games:

  1. Symbols

From the very first slot machine, the basic symbols are still being used today, including lemons, cherries, 7s, and liberty bells. But in online slots, the range of symbols is limitless. In addition to that, there are also lots of other features that you need to be aware of. Here are some of them:

  • Wild Symbols: These symbols turn into any other reel symbol to create a winning pay line.
  • Multipliers: These symbols multiply your bet. They can start at 2x and go as high as 5x.
  • Free Spins: These symbols allow the players to spin for free. It can be triggered as a bonus or randomly during a spin.
  • Scatter Symbols: These provide wins multiplied by the total bet. It also triggers bonus rounds like jackpots and free spins.
  1. The Reels

The reels are where the symbols on the slots are printed. Typical slot machines and online slot games have three reels. But there are some with four, and others have as many as six. Most reels have 20 to 24 steps or stops, and each of them has a symbol, like cherry or lemon, or it can also be a blank, which doesn’t help.

  1. The Payline

This is probably the most important part of any online slot machine. It can be one or more horizontal or diagonal lines that are marked on the window in front of the reels. It is basically the visual display that shows players if they have scored a winning spin or not.

  1. The Payout Display

The payout display is also an important part of slot games as it shows what combinations are needed in order to have a winning spin and how much each of them will pay. On a straight slot machine, all the winning amounts are posted on display. These are usually expressed in the number of coins that can be won as opposed to specific currency amounts. For example, a winning combination might show a payment of 50 to 100 coins.

  1. The Buttons

You can find many buttons on an online slot. Here are some of the most common ones that you might encounter:

  • Bet Max Coins / Play Max Credits

When you press this button, it will bet the maximum amount of coins allowed and will spin the reel automatically. For example, if the machine accepts ten coins as a bet, pressing the Bet Max Coins button will deduct ten coins from your credits.

  • Play One Credit

You also have the option to play one coin at a time by pressing the play one credit button. Also, the reels will not spin until the handle is pulled or the ‘spin reels’ button is pressed. You also have the option to press this button twice or thrice.

  • Cash Out Button

You can also use your credits by playing them through until the total is zero. Aside from that, you can also press the cash-out button, which will convert credit into actual coins and transfer them into your virtual account.

three slot machines in a casino

A bank of reel-spinning slot machines


How to Choose the Right Slot Game

If you plan to play slots online, you need to choose the slot game carefully. Online casinos tend to offer thousands of slot game titles. Here are some tips you can follow in choosing the best one for you:

  • Choose a slot game that suits your budget: Check the minimum and maximum bet allowance of each slot game and pick one that suits your budget well.
  • Choose the number of pay lines that you like: Keep in mind that the more pay lines, the higher your chances of winning. But there are also players who choose to stick to the traditional one-pay line slots.
  • Look for a theme that you like: To have a more entertaining game, try to find a slot game that has a theme you like. This can make the game more fun.
  • Don’t be afraid to try out different slot games: Since there are a large number of slot games online, it might also be fun to try various ones. If you don’t enjoy one, then you can always stop playing and find another one.


How to Play Slots Online

Here are some of the steps you can follow in playing online slots:

  1. Check out the pay table: Before you start playing, try to familiarize yourself first with the pay table. Take note of the wild symbols, scatter icons, and what you need to land on to be able to trigger the bonus options.
  2. Set the number of lines and the bet per line: The amount that you will bet depends on you, but it is recommended to play the maximum number of lines.
  3. Step by step guide: First, you will need to choose whether you want the slot to play automatically or not. If you don’t want it to spin automatically, these are what you need to do:
  • Click on the ‘Spin’ button.
  • Watch as the reels spin and come to a stop and reveal any pay line wins or triggered bonus rounds. If you receive a bonus, the instructions on how to use it will be displayed.
  • Following the completion of your spin or bonus, repeat the process.



Slot machines and online slot games are indeed some of the most popular casino games in the world. Due to their easy mechanics and huge prizes, many people are into playing them and taking their chance. Just remember that when you play slots and any other casino game, you need to manage your funds well and never spend more than what you are willing to risk.

Always keep in mind that these are just games for entertainment and winning some money is just a bonus. Focus on having fun and always know when to take a break or stop playing. We hope this post helped you learn more about playing slots.

Matt Bourie is the editor of the American Casino Guide book. He has been writing about casinos for more than 12 years and he also
co-hosts the American Casino Guide YouTube channel which has had more than 40 million views. A new video is released each month
that discusses a new casino gambling topic and you can subscribe for FREE at