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How do online slot games work

How do online slot games work?

This is the question that every slot player wants to know the answer to and we have the answer!

Here’s the deal

Slot machines work with a different mechanism today compared to the past. Gone past the days when the first slot machines contained five drums holding a total of 50 card faces and the player had to insert a coin and pull a level which would spin the drums.

So what if we told you that they way sot machine games work today is much more complicated, but we can still understand exactly how they work?

On this page we look at the details of how the new technology works so slot players can understand better what is happening when they click on the Spin button!

Modern video slot machine games are now much more complicated in the way they work, are fully electronic and are using a Random Number Generator (RNG) to produce the results that we see on our screens.

How do online slot games work and the RNG

This is the case also with online slots or slot machines in brick and mortar casinos or betting shops. But how do online slot games work exactly from the time you press that Spin button until you see the symbols on your screen?

Let’s start with the basic mechanism behind the modern slot games, the Random Number Generator.

What exactly is the Random Number

The Random Number Generator (RNG) is an electronic mechanism/software that all slot machines online or offline are utilising. This software is used to produce the algorithm that slot games need in order to determine which symbols are going to appear on the slot game screen every time.

this is the definition of Random Number Generator in wikipedia

Random number generation is the generation of a sequence of numbers or symbols that cannot be reasonably predicted better than by a random chance, usually through a random-number generator (RNG)

The Random Number Generator is working continuously and without stopping once the online video slot game comes to life, producing random numbers from 0 to some million. If you want to see how a Random Number Generator works in practice you can visit

  • The RNG produces those numbers independently if there is a spin or not
  • The RNG does not get affected from external factors
  • These numbers are totally random
spiderman slot game

When the slot player clicks on spin, then the slot will automatically receive the numbers that the RNG has produced at that time, will process them and bring on the screen the equivalent symbols to those numbers.

These numbers are totally random and that’s why there are exactly the same chances for someone to win the maximum amount on the spin, free spins, bonus rounds, the jackpot or absolutely nothing.

Someone can win or lose 10 times in a row as a result of the randomness of the results. The Random Number Generator is applied to all online casinos, so when you play online slots they are all ruled by the RNG

This is the simple explanation of how online slot games  work, but what is the exact procedure from the RNG to the screen?

How do we end up from the random number generation from to the actual process and production of the symbols in our screens?

The numbers that come out of the Random Number Generator are numbers that equal to specific places in the slot reels. The slot processor receives that number and then divides that number with a computer value 16, 32,64,128 etc that differs depending on the slot.

The result of that division is the one that determines the symbol that will appear on the slot game screen. The first digit determines the first reel’s position, the second determines the second reel’s position, and the third determines the third reel’s position, and the same is true for five-reel slots and other slot game variations.

The Random Number Generator software is rigorously tested before use to ensure that the outcomes are free from manipulation, and thus fair and safe.

All the reputable online casino sites will have RNGs that are certified by the Gaming Labs (GLI) . Despite the fact that modern online slot machines have changed during the years due to more sophisticated  and developing gaming technology, the fundamental aspects of the Random Number Generator always remain the same.

Now you should have a better idea about the mechanism behind slot machine games and  be able to answer of the question ” how do online slot games work ” if another slot player asks you!

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If you prefer a more visual explanation, you can also check out our slot games infographic “How do slot games work” below.

slot games infographic 500

Types of slot games

So now that we know how slot games work and we have and you are aware of the random number generator lets have a briefly look at the types of online slots that use RNG.

  • 3-reel slot games

There are also know as single line slot machines and are the siplest slot games you can find online ( and offline of course)/ If you are a newcomer and dont want many complicated lines, reels, payouts etc then these re ideal.

  • Video slot game or multiple reel slot

Mutliple line slots or video slotsare the most popular slot types online and these online casino games are also referred to as 5-reel slots. The sounds, images, and graphics of these games are attractive, sophisticated, and designed to enhance the players experience of the game significantly. These slot games have features like bonus riunds, free spins multipliers and many more. The Random number generator works on these features the same way as in a normal spin. But as soon as you hit the free spins round then the payout is already determined by the algorithm.

At this stage we need to clarify that it doesnt matter what type of slot game you play when it comes to payouts. The highest return to player slot games are a mix of single line slots and mutliple line slots which proves that point. Check out our online slots reviews to find out each game’s RTP and more info or just visit our best slot bonus page to find a reliable UK casino!