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What is a Random Number Generator in slots?

Known as the ‘brain’ behind slot machines, the Random Number Generator is what makes slots what they are: games with a completely random outcome that’s independent of previous outcomes. In this article, we’ll have a closer look at how a slot Random Number Generator works and explain why it’s so important for online slot players to understand its purpose.

So what is a Random Number Generator exactly?

A Random Number Generator (RNG) is a microprocessor that makes use of a special program to constantly generate random numbers (nowadays it’s actually a computer chip or process with the same function). These numbers, which correspond to different reel positions in slots, will then determine the position of the reels in a given game. Depending on the specific formula used, a single reel can have just a few numbers assigned to it, or even billions. Each number corresponds to what is called a ‘stop’, so that the reel will stop spinning at a specific location.

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If we take online slots as an example, as soon as you click the spin button, the RNG produces this random number within a millisecond, so that even if the reels continue spinning, giving you the impression that the outcome is still undecided (and prompting you to keep your fingers crossed, pray or beg the goddess of luck), in reality, the outcome has already been determined as soon as you clicked that button.

Apart from online slots, there’s a random number generator behind any online casino game, be it keno, video poker or table games. This means that there will be a number to correspond with every outcome, which is then expressed as a reel position, keno number or playing card, depending on the game in question.

Random Numnber Generator

Can online slots still be rigged if there is an RNG?

If online slots are offered by a casino that’s licensed under a regulated jurisdiction (such as the ones we recommend here, which are all licensed by the UK Gambling Commission), you may rest assured that there is a Random Number Generator at play and that none of the games are rigged. However, this doesn’t mean that there is no house edge. The games are still programmed to give the online casino an edge (how would they be able to make money and keep the business running otherwise?).

The programmer behind a slot can assign a different amount of random numbers to different symbols. Just by way of example, one may choose to assign 10 random numbers to the cherry, whereas a lower-paying number will be assigned 80 of these numbers, so that there would be a higher probability of landing on a less lucrative combination.

So just to clarify: the programming behind an automated game is not random, but is meant to give the casino a slight edge. However, the programmed RNG will then run randomly, i.e. it will generate all the possible combinations at random.

One word about RTPs

Speaking of programming, the game Return to Player, or RTP, is worth a mention here. Normally, you can see how much you can expect a slot to pay out by consulting this percentage figure. This ranges from 92% to as much as 99%, but for most online slots it’s somewhere between 96% and 97%. This means that for a theoretical number of rounds, the game is expected to pay back £96 for every £100 staked. But one word of caution: this number is theoretical, determined over thousands of spins, and it doesn’t guarantee that you’ll never lose more than £3 for every £100 you stake (or that you’ll never win much more than you stake!).

If you’re interested to see which slots pay out the most, we suggest you have a look at our article on slots with the best RTP here.

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What does the Random Number Generator mean for slot players?

Quite simply, it means that with a Random Number Generator, the outcome for each spin is completely random, and independent of previous spins. Getting a dozen non-winning spins doesn’t mean that you’re close to landing on a win, and vice versa, if you’ve just won a jackpot, that doesn’t mean that you won’t land on a win on the very next spin (we admit, that would be one lucky streak, but you get the meaning…). The program just doesn’t care whether you’ve been winning or losing!

For slot players this means that it is completely useless to expect a slot to pay out on your next spin just because you haven’t won for a while. This mindset would most probably lead to losing much more than you win, since you keep hoping that you’re closer to a win, and will keep staking your money and risk losing more. In reality, the only 'strategy' you can employ is to set a budget for yourself. You should to decide in advance what you can afford to lose on a given day/week/month and stop playing once you reach that limit. This will keep you and those around you happier!

Find a fair casino and bet wisely

And now that you've learnt all about Random Number Generators, it's time to pick a slot to your liking and play it with a fair and secure casino. For a casino to be deemed fair, it's not enough to guarantee that there's an RNG behind every slot; its bonuses and promotions also have to be subject to fair terms, and the way it handles player data and bank details has to be secure. You may consult our list of UK online casinos which have been tried and tested, and which we continue to promote because of their rewarding bonuses and their huge collection of slots.

And remember, every outcome is completely random, so be wise and stay within your budget. Never expect a slot to have pity on you (it's neither god nor human). That said, never stop dreaming, just keep trying within limits!

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