The Maths Behind Slot Machines

Slot games might look all flashing lights and colourful reels, but behind the graphics, there's a carefully built system designed to keep things fair and fun. Whether you're spinning for the first time or you've played plenty of online slots before, understanding the maths behind slot machines can help you enjoy the experience with more confidence. 

In this guide, we dive into the key math terms behind slot games and what they mean for your play. 

What Makes Slot Outcomes Random? 

Every spin on a slot machine is determined by a Random Number Generator, or RNG. This is a computer algorithm that produces thousands of number combinations every second - even when nobody is playing. 

When you press the spin button, the RNG instantly selects a combination that determines the outcome. 

There's no pattern to follow, and no memory of previous spins. So, whether you've just hit a big win or haven't landed a bonus in a while, the next spin is just as random as the last. 

Key point: There's no such thing as a slot machine that’s "due" a win or one that's "on a streak." The randomness is what makes each spin fair.

What Is RTP and Why Does It Matter? 

RTP, or Return to Player, is a percentage that shows how much a game pays back to players over time. For example, a slot with an RTP of 96% is expected to return £96 for every £100 wagered in the long run. 

It's important to note that RTP is a theoretical average based on millions of spins. It doesn't mean you'll definitely get £96 back for every £100 you spend. In a single session, you could win more, win less, or not win at all. Game developers include the RTP in every slot they create, and it's reviewed by independent testing agencies to make sure it's accurate. 

If you're curious about which games offer the highest theoretical payouts, we've rounded up a few in this guide to high RTP slots.

Volatility: How Slot Games Pay Out 

If RTP tells you what a game pays back over time, slot volatility helps explain how those payouts are delivered. In simple terms, volatility describes the balance between how often a slot pays out and how big those payouts tend to be. 

• Low volatility slots offer frequent wins, usually on the smaller side. These games are often steady and suited to longer sessions. 
• Medium volatility slots aim for balance; wins might not come as often as in low-volatility games, but when they do, they can be a bit more substantial. 
• High volatility slots pay out less frequently, but the potential wins can be bigger. These games may have longer dry spells between wins, but they often come with bonus rounds or big-hit potential. 

There's no "better" volatility; it just depends on what fits your playstyle. Some players enjoy a smooth experience with regular activity, while others prefer the excitement of bigger - but less frequent - wins. 

You can often find volatility information in the game's help menu or get a good clue by checking the paytable and bonus features.

Hit Frequency: How Often Do Wins Land? 

Hit frequency is the average number of spins between wins. For example, a game with a 25% hit frequency will produce a winning combination on roughly one in four spins. 

This stat can help you understand how "busy" a game feels. Higher hit frequency equals more regular wins, though not necessarily big ones. Lower hit frequency often means fewer wins, but with the potential for bigger rewards when they do land. 

While not always displayed in-game, some providers include hit frequency in the game rules or description.

What About Bonus Features? 

Bonus rounds, free spins, multipliers, cascading reels; these are all ways slot developers add variety to gameplay. 

Behind the scenes, these features are factored into the overall game maths. So, if a game includes a high-paying bonus round, the base game payouts may be slightly lower to balance things out. 

That's not a bad thing; it just means the entertainment is spread out differently. And for many players, bonus features are a big part of the appeal.

Can You Improve Your Chances? 

This is one of the most common questions around slot games. And the answer is: not really. 

Because RNGs make every spin random, no strategy or system can change your chances of winning. Slots aren't like poker or blackjack; there's no decision-making involved after you spin. 

But while you can’t influence the result, understanding how games work can help you make smarter choices, like: 

• Look at the RTP to see how a game's returns are structured over time - some players prefer higher RTPs, while others focus more on features or themes. 
• Consider volatility to match the kind of session you want: steady gameplay or the potential for bigger, less frequent wins. 
• Manage your session by setting time and spend limits that suit you. Knowing how long you want to play - and when to call it a day - can make the experience feel more enjoyable and in control. 

Behind the Reels, It All Adds Up

Slots are designed to be unpredictable, and that's part of what makes them fun. But even though each spin is random, the way games are built isn't. 

Behind the reels is a set of rules and systems that ensure fairness, balance, and variety. By understanding things like RNGs, RTP, and volatility, you're not just spinning for the sake of it; you’re spinning with insight. 

At Virgin Games, we're serious about play. That means not just offering a wide choice of thrilling slots, but also helping you understand what goes into them. Whether you're going for bonus features or just in it for the spins, knowing the maths can help you play your way. 

And yes, you can do it all from your mobile. Find out how to play slots on your phone for real money, wherever and whenever suits you.

Curious to see the maths in action? Join Virgin Games today and explore thrilling online slots with varied RTPs, volatility levels, and bonus features. All designed to suit your playstyle.

All offers mentioned correct at the time of writing but may be subject to change.