How do Slot Machines Work - Slots and Tables

How Slots Work

Slot machines are the most popular games you can find on the casino floor. The main reason for this is that slots are incredibly easy to play, as you don’t need to learn any rules or strategies in order to optimise your chances in winning.

Every player can become a slots master right off the bat, making slots especially popular among newbie players. Slots can also produce massive payouts, even while playing on minimum bet, which is another reason for their popularity. But as simple as they may look slots are in fact complex machines, with a lot going on behind the reels. So, how do slot machines work?

How it Work on Screen

In order to understand how slots work you first need to understand what’s happening on the screen in front of you and what options you can adjust. Let’s start with the basics, the reels.

Slot Reels and Rows

Today slots usually come with 5 reels. This is a vertical stack where usually 3 symbols land on each spin if you’re playing modern video slots. At the same time, older slot machines come with 3 reels, while some more unusual slots can have 6 or even more reels. 

A row is a horizontal stack of symbols which goes across the reels. Usually, slots with 5 reels come with 3 rows, but the number can differ from one slot to another. 

Pay lines / Ways to Win

Pay Lines are lines where matching symbols need to land in order for a win to be formed. The number of pay lines in slots can differ, starting from only 1 up to 100 or even more. There are also slots which use a Ways to Win design, meaning that you only need to land matching symbols on the first 3 adjacent reels, regardless of their position.

With added rows and reels some of these slots offer a massive amount of ways to win and can produce massive payouts in return. 


Each slot machine comes with its own game symbols. What’s common about most slots is the presence of a Wild, Scatter and Bonus symbols. The Wild symbol usually replaces all other regular symbols from the paytable and in many cases comes with an added function, like a Win Multiplier.

The Scatter symbol, on the other hand, is usually responsible for triggering the bonus round, when 3 or more hit the reels. The Bonus symbol has the same function as the Scatter and is usually added when the slot comes with more than one bonus feature. 

How slots work – Behind the Scenes

Now that you know what’s happening on the screen in front of you it’s time for some in-depth info on how actually slots work and what makes the reels spin. Let’s begin. 

slot reels

Random Number Generator

The Random Number Generator (RNG) is a piece of software which makes sure that every spin on the slot machine is completely random. Thanks to this you can never predict what the outcome of the next spin will be, based on the previous spins in the game. The RNG is what makes slots random machines, where the outcome is based only on luck rather than on skill. 

If you’re interested in reading the mechanics behind RNG here’s a good article

Return to Player

Slots RTP

Each slot has a predetermined Return to Player (RTP) value. On online video slots, this value is somewhere around 96%. This means that over a big number of spins and a long period of time the slot is predicted to return 96% of all bets in form of winnings. Based on this info, players can choose to play slots with a higher RTP value and expect to get better payouts in return. 

How Slots Work With Variance

The slot variance is what many players refer to as “factor of luck”. The variance determines the frequency of payouts on the reels. Low variance slots produce frequent, smaller payouts, while high variance slots pay less frequently, but the payouts can be much bigger in size. 

So, these 3 factors are what makes slot machines spin and which makes them so fun and addictive at the same time. The reality is that slots are games of chance, without any factor of skill whatsoever. This is what makes them so easy to play. All you need to do is set your bet and hit the spin button. From there on it’s all up to lady luck on whether you will win or lose. 

Are Slots Worth Playing?

Now that we’ve answered how do slots work question, you may be wondering, are they still worth playing? Just because slots are games of chance it doesn’t mean that they are not profitable. Quite the contrary. Some slots with a high variance and a rich paytable have the potential for producing massive payouts.

This is even true for low RTP slots like progressive jackpots. You have a chance to win millions of dollars while playing on a minimum bet. Yes, the chances for this are astronomical, but you never know what can happen with some luck on your side.