How does a casino slot machine work?
7 min left

How does a casino slot machine work?

Online casino slot machines operate in a very specific way. From a higher-than-average RTP to a very specific theme, from a 3-reel slot machine to one with 5 reels, there are all kinds. 

To fully understand what a slot machine is and how it works, we'll take a look at everything you need to know before playing one. 

How a slot machine works

From the animations used to the various bonuses made available to you, slot machines operate in a very precise way. 

Before presenting a game to you, game suppliers work for months to get everything just right. 

Volatility, animation, functionality, bonus purchases - the companies think of everything to make sure you have the best possible time. 

That's why, before choosing a game, we advise you to look at several pieces of information about it: RTP, maximum win, volatility, etc. 

We know that some people find it hard to understand how all this works, and that's why we're going to explain it all to you. 

Don't hesitate, you can play slots at Casimba Casino! 

Winning lines 

The basis of a slot machine is its connections. There are several different types, and they don't all work in the same way. Here are the most common connections: 

  • Cascades¬†

  • Megaways technology¬†

  • Megacluster technology¬†

  • Connection with classic lines¬†

Depending on what's used, the payout won't be the same. 

In Play'n GO's Book of Dead, for instance, 5 explorer symbols (the best symbol) pay 5,000 times your initial bet. This slot uses 10 different paylines. 

On a Megaways slot like Big Bass Bonanza Megaways, however, the value of the top 5 symbols will only earn you 25 times your initial bet. 

Slot machine reels 

Depending on the slot machine you choose, several different types of reels will be offered to you. 

When playing John Hunter and the Book of Tut Megaways, you'll find 6 different 

What makes Megaways games so special is that the number of symbols in each column varies with each spin. 

Slot machine reels in John Hunter and the Book of Tut Megaways

Reactoonz from Play'n GO is a slot that features a fairly large starting grid, made up of 7 columns with 7 symbols. Here, connections work with clusters. 

These reels are quite unusual. 

The final, rather atypical line is Roman Legion Xtreme. This game offers 2 starting lines: 

  • One with 5 columns and 3 symbols¬†

  • One with 5 columns, but 9 symbols inside¬†

We especially love playing this game, which is really quite volatile. 

In reality, however, there are only two classic starting grids: One with 5 reels and the other with 3 reels. 

3-reel slot machines 

Three-reel slots have been a staple of online casinos for many years. They're easy to understand, which is why we like them so much. 

Generally speaking, they have very low volatility. 

We recommend them if you want to dip your toes into the world of slot machines, because they're quite easy to understand. 

Don't hesitate to try out the 3-reel slots at Millionz Casino! 

5-reel slot machines 

5-reel slot machines are the most common types of slots. They usually feature 5 columns with 3 symbols inside, as well as 10 paylines. 

They can be highly volatile, like Pragmatic Play's The Dog House.

A game like Dragon Hero also features a 5-column starting grid, but with 4 symbols inside. 

How slot machines work 

It's easy enough to understand how slot machines work. 

First of all, they are made up of several features: 

  • Precise graphics¬†

  • Different stakes¬†

  • Different symbols¬†

  • Different paylines¬†

  • Features (bonus buy-ins, etc.)¬†

Each game also has a specific volatility and Theoretical Return to Player (RTP). 

It's up to you to start the rounds. Either you do it with your mouse, or you launch an option that allows you to activate the rounds automatically. 

Many game providers, like Play'n GO, offer this option. 

The Random Number Generator 

The Random Number Generator (RNG) is a technology that allows you to understand the outcome of a game round. 

The reason this technology is so widely used is that it ensures that each game round is generated at random. 

As a result, it's impossible for an online casino or gaming supplier to rig the results. 

Every company offering its slot machines is obliged to have this technology if it wishes to operate in legal markets. 

To verify that this technology is not rigged, external companies carry out frequent audits. 

Gaming Labs Certified is the most reputable auditing company and has, for example, validated Pragmatic Play's RNG. 

That's why we always advise you to play at regulated online casinos and gambling operators. It is important to ensure that these are in possession of a reputable gaming license. 

These include Millionz Casino, MyEmpire Casino, and Casimba Casino, three exceptional online casinos that we highly recommend. 

Lucky7Bonus' top slot machines 

The slot machines that we're about to introduce to you are among our favorites. They have everything we love: 

  • High volatility¬†

  • High maximum winnings¬†

  • Lots of features¬†

Of course, this is not a ranking. These are simply the slot machines that we play the most. 

Feel free to shift through the wide selection of slot machines that are available on our site and play some of the most popular slots completely for free! 

Starlight Princess 1000 

If you like volatility and explosiveness, Starlight Princess 1,000 from Pragmatic Play is a slot we play a lot. 

During the base game or free games, you can win up to 15,000 times your initial stake. 

We really like the graphics, which perfectly reproduce the world of the first version of the slot. 

Sometimes we just don't like playing rounds, which is why the bonus purchase feature is perfect. 

Book of Dead 

With 5 reels of 3 symbols, Book of Dead is an online casino classic. 

Although it doesn't offer the bonus purchase feature, this game has other advantages: 

  • Easy to understand¬†

  • Highly volatile¬†

  • Perfect for online casino beginners¬†

This is a game we play a lot when we're on a bonus hunt. The bonus drops quite regularly and allows you to win up to 5,000 times your initial stake. 


Nolimit City's Deadwood is a highly volatile game with a payout of 13,590 times the starting stake. 

The game features a highly volatile base game, as well as several bonus purchases. 

Did you know that by clicking anywhere on your screen, you'll be able to "shoot" two bullets through it? 

If you didn't know, don't hesitate to try out this exceptional slot machine at Playfina Casino. 


AvatarUX has built its reputation on one slot machine: CherryPop. 

We love this slot machine, which has introduced a betting feature for bonuses. Even when you manage to obtain the maximum number of free spins, you're not even sure you're getting paid. 

The graphics are sublime, and the volatility is explosive. 

The final highlight is its progressive connection system, in which the starting grid increases with each connection. 

Razor Returns 

Push Gaming's Razor Returns is a highly volatile slot machine. In it, a maximum payout of 100,000 times your original stake awaits you. 

We love this game for its extreme volatility. The base game offers some nice payouts, thanks in particular to the coins available.  

In addition to this, the free games can be equally generous, and in this game, you can also bet your bonus. 

In fact, you can buy up to 5 different bonus games. Our favorite is the one with coins. 

About the authorMelanie Cazenave
63 articles
‚úÖ Reviewed by Head of Content
Expertise :
A specialist in online casinos, she also loves proofreading. With her, it's impossible for mistakes to slip through the cracks. A true lover of letters, she binds articles and retouches them to make them as perfect as possible.

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