How Are Slot Machines Programmed?

| Oct 11, 2019

When it comes to popular games at online and offline casinos, slots come at the top of the list. While huge numbers of people play them, not many know exactly how they work though, meaning that many myths and untruths have popped up regarding the world of slot machines.

On this page, we’re going to show you how a slot machine is programmed. This will include both online and offline machines, as they are both programmed in pretty much the same way. We’ll also let you know how slot machines are programmed to make money in the long term – something that ensures slots are viable from a business perspective.

How Are Slot Machines Programmed?

Slots Use a Random Number Generator

The most important part of any online slot machine is the random number generator, as this determines which symbols land on the reels. Basically, there are many different combinations of symbols that can appear, and each combination is assigned its own number. When the reels are spun, the RNG will select one number and this will govern the result.

It should be mentioned that the RNG of a slot machine really is truly random. This means that slots aren’t set to pay out at specific times, and you’ll always have the same chance of winning the jackpot, regardless of whether it’s not been won for weeks, or it was won an hour ago.

RNGs are programmed by experts, who understand the exact mathematics behind slot machines. Programming has to be exact, to ensure the slot doesn’t pay out too much, as well as to ensure that the slot meets its RTP – a subject we’re about to discuss next…

Understanding the RTP at a Slot Machine

It’s very important to understand that while every spin is random, a slot is programmed to pay out only a certain percentage of what is spent on it, and this return is called the Return to Player (RTP). For example, a slot might have been programmed to have a 95% RTP, and this means that, over a long period of time, the slot should pay out £95 for every £100 gambled on it. The higher the RTP, the better your chances are of winning. You can see the RTPs of slots at most online and mobile casinos.

Just because a slot has a 95% RTP, it doesn’t mean you’ll definitely get 95% of your money back though. Think of it like this: if someone spends £1 and wins £10,000, this will mean that many other players will have to lose their money in order to balance the books. This is done by using probability and by the developer trusting that the probability will be true over a very long period of time.

Slots Are Programmed to Have an Edge

Something that is really important to remember is this: all slot machines have a slight house edge. If they didn’t, the games wouldn’t be making any money, therefore meaning that there would be no point in the developers offering slots in the first place.

Some might think that this house edge, which is typically 2% to 5%, is unfair and an example of how slots are rigged. We disagree though, as we don’t think it’s rigging when the player already knows that a house edge exists. If you are looking for a casino game that doesn’t have a house edge, you’re better off playing some forms of video poker found online.

Charles Baxendale (BSc, MSc Mathematics and Computer Science)

Charles Baxendale

(BSc, MSc Mathematics and Computer Science)

A keen researcher in the development of methods and theories for computer sciences. A lover of algorithms and mathematical computation. Consultant to online slots software companies and a player in my spare time.