How Do Slot Machines Work

Published 2 Nov 2018, 10:32 a.m.

Originally, the casinos installed slot machines to bring diversity in their casinos to the casual gamers. The traditional table games like blackjack, baccarat, roulette, carps and many others were a bit too complicated for the person that wanted to gamble but had no idea how to play some of these casino table games.

The slot machines were a thing where you could gamble with no previous gambling knowledge and with a very small bet. The idea came out to be a huge success – eventually, the slot machines moved in their own direction and became the most popular and most profitable machines in the land-based casino. They were bringing more than 60% of the annual profit in the States, but how do slot machines work?This is a question asked by many of the online slot lovers which want to have a deeper understanding of the machines they are playing, so let’s answer this question as much as we can.

How Do Slot Machines Work?

The technology hasn’t changed a lot over the years, and although the mechanics of the game completely changed and replaced with computer controlled machines, the basics and core of the game remained the same. The player needed to pull a lever to start the (usually three) reels spinning, and now it’s done by pressing the spin button on the screen. The main thing to look in this game is to land the symbols on an active payline, and that’s how what determines whether you win or lose – by the pictures which are printed on the reels of the slot game. In the past, there was one active payline in the middle of the reels and almost all the symbols were the same, but now there are games with up to 10,000 or more paylines, but the standard has moved to a 25 paylines average. If all of the reels show the same page on that line, that’s when you will grab a win, depending on the value of the symbol that you’ve managed to land.

Pulling the Handle

Pulling the handle orders the machine to work its magic. The handle is pulled towards the player and every particle in the machine starts rotating, together with the reels. A catch on the opposite side of the lever inside the machine pulls the lever back to its original position, making it ready for the next pull, and after few seconds of spinning, a lock stops the reels in place and it determines whether you are lucky or not. With the online slots, it’s all automated and you won’t notice anything but the motion of the reels as soon as you press the spin button.


There are several different payout methods in the online slot machines, but we will stick to one of the simplest designs to make sure you understand properly. Let’s go back to a machine that understands one coin and has only one winning combination.

When you insert a coin, it lands in a transparent case with a movable bottom which is always ready to pay out for the luckiest player. With three different disks, one for small payouts, one for medium and large and the last one for the progressive jackpot, the disc would shift to the required position ordered by the symbols that land on the reels.

Typically, slot machines will have more elaborate versions of this design in order to pay out partially on certain combinations of images and pay out completely on the jackpot combination.

But things moved a long way since this time, and the number of people who are going in casinos and actually playing these types of slot machines reduces drastically as the days go by, and the online casinos are taking over. The player can use its computer, laptop, tablet or even the mobile phone to access the casino games. They are quite different now, and many things have changed from what we mentioned above.

 Computerize Slot Machines

The most modern slot machines are designed to look exactly like the original slot machines. They have the same screen, the same position of the logo, features, paylines and buttons on the screen, but they operate completely different. The outcome that you see on the reels is controlled by a microprocessor (computer) which is located inside the computer instead of the motion of the reels like it was in the past slot machines.

There are step motors to turn each reel and stop at the point when you hit the stop button. They are computer controlled rather than the ordinary electric motor which was the thing with the land-based slot machines. This may sound a bit odd for some players, thinking that the computer is pre-programmed to pay out at a certain time and to show a certain combination on the screen, but this is completely untrue.

At the heart of the slot computer, a Random Number Generator is a place, making sure every single player, every single spin in every time has the same chances of winning the jackpot. The Random Number Generator, also known as the RNG, supplies up to several thousand numbers in a second, and those numbers determine the symbols that you see on the reel. The moment you hit the spin button or pull the lever (in the video slots with a lever, which also used RNG) the computer remembers that particular number which was spilt out by the RNG and that determines what you’ve won.


How do slot machines work? Now you know, and even though it’s different from the land-based machines that used to be hit in the past from the online slot machines nowadays, the concept is the same – every player gets an equal chance of winning each prize which the machine offers.

If you loved this article and want to get familiar with something else on the slots topic, check our blog, or head to our games section to see the slots in action.