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What Algorithm Do Slot Machines Use?

Online Casino, Entertainment

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Source: pxfuel.com

When spinning the reels of your favourite slot at an online casino, it’s a smooth and simple process on the surface. You place a bet, the reels spin, and relevant payouts are made.

But there is a great deal more going on than meets the eye.

Online slots are actually part of a vast, intricate design. A design that took a great deal of time and effort to perfect. Slots, after all, are based on the principal of truly random outcomes, and as far as human ingenuity is concerned, that is no small ask.

After all, just how many systems do you know of that make use of truly random outcomes that can be generated at a seconds notice?

To look at it another way, the moment that slots went digital an enormously complicated and intricate switch had to be made. Namely, the switch from a mechanical random system to a digital one. Dealing with the concept of randomness is never an easy prospect, and it was certainly an overwhelmingly difficult process when slots used physical parts. A solution was found, however, and reel spinners were satisfied that the results of each spin were indeed random.

However, the ‘true random’ challenge was equally as overwhelming when taking the task to the digital world. It was such a difficult task that, for the longest time, many even argued that the concept of a truly random outcome was all but impossible.

However, using incredibly innovative techniques the random challenge was eventually overcome, and in process the digital RNG microchip was created.


The abbreviation RNG, otherwise known as random number generator, is referred to a great deal these days. Many use the term to simply refer to an outcome in the digital world that is technically unknown. Such as in various video games. However, when getting right down to it, the RNG used in slots is a great deal more advanced than most assume.

An online slot RNG is generating numbers on a constant basis. Importantly, the numbers are generated on the side of the server, not on the side of the device that is being used to play. Billions upon billions of random numbers are being generated constantly, every second, even when the reels aren’t being spun.

In fact, so many numbers are generated on such a constant basis that it is all but impossible to have any clue which numbers are currently occupying the RNG space at any given time. This is, of course, the very basis of the system, and the core of what makes each spin of the reels so truly random.

When the reels are spun, a call is sent to the server that quickly refers to the RNG. Once the information is received, the reels land in the position generated. Of course, there is nothing that anyone can do, ever, to alter the outcome of the RNG. It is truly random in every sense of the word.

Deeper Functions 

It is important to understand that the RNG system is separate from the functions of actual slot software. The reels, graphics, theme, audio and everything else is all created separately, and designed to have RNG fed into it. This means that no matter what occurs on the end of the game interface, the RNG will never be altered, and is always impartial to what is occurring.

Hence, anyone who believes that there is some sort of sequence to online slots simply doesn’t understand how the process works.

But what about hit frequency? Very simply, hit frequency is just another part of the RNG system. It is randomly generated, along with all the other numbers, with hits coming up at a predetermined random rate.

To put it another way; the amount that a slot results in a hit, or a winning payout, is as random as every other spin, and simply part of a mathematical equation. Once again, nothing will ever alter this function, or push it towards being more or less frequent.

But does this mean that all slots have the same hit frequency?

No, of course not.

Different RNGs simply operate with different mathematical percentages. It is not a case of one RNG fitting all games, else we would be in a situation where every single slot felt exactly the same. That wouldn’t be particularly fun now, would it?

Different RNGs are designed to have varying overall payout and hit percentages, which helps to distinguish between different kinds of gameplay.

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Source: pxfuel.com

Payback Rates

As a general rule of thumb, RNGs will either be referred to as loose or tight. But this certainly does not mean that some RNGs are simply more prone to generating higher overall payouts than others. Instead, it is a balance that is found between the rate of hits, and the generosity of the payout percentage.

To put it another way; an RNG will either payout frequently, but with lower payout amounts, or less frequently with higher payout amounts. In the long run, both are paying out similar overall amounts. It is just a matter of how much is paid out over any given period of time.

Players tend to either find one or the other style more engaging, and naturally lean towards this type of gameplay style. But, once again, neither style is really more generous than the other. It all ultimately still fits elegantly into the base RNG philosophy, and stays true to the principals of fair reel spinning.

A Ballet Of Randomness

Needless to say, RNG systems, and the slot software that makes use of them, are under constant scrutiny. Countless tests have been run on the systems, with critics attempting to find some sign of a pattern, or a predictable outcome. It goes without saying that no flaw has ever been found in RNG, and will undoubtedly never be found. There is no question that the billions of numbers being generated every second are not observable in any way.

With that being said, it is widely agreed that the RNG in online slots is an incredibly impressive achievement, and that an enormous amount of work has gone into keeping the results truly random. That each spin can be truly unknown is no small achievement in the digital world, especially given how intricate and flashy online slots have become. But lest it be forgotten, no matter how much the slot software itself evolves, the same RNG is still being used.

All in all, every reel spinner can rest assured that no matter what, the results of their favourite online slot will be 100% fair.

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