What is a Random Number Generator?

Many casinos boast about their random number generators when they list their credentials and features in order to entice players to try their games. The thing is, though, that a large number of players – particularly those with little experience in online gambling – have no idea what a number generator is and why it should be random.

So, what is a random number generator? Random number generators or RNGs are computer programmes that online and land-based casinos use to replicate the element of chance in their slots games. In card games and roulette, chance is a natural phenomenon resultant of the shuffling of the deck or the spinning or the reel – no one can predict the order in which the cards will come up or when the wheel will stop.

With online slot machines, however, this natural unpredictability is eliminated and so must be artificially created. This is where RNGs come in and begins to answer the question: “what is a random number generator?”

How Do RNGs Work?

In reality, it’s not necessary for a player to completely understand the complex mathematics of RNGs to able to answer the question: “what is a random number generator?” However, it is reassuring to know the basics.

Let’s say the symbols in a three-reel slot game include cherries, 7s, gold bars, bells, plums and lemons. This means that, on each spin, any one of these six symbols could come up on each of the three slots – 343 possible combinations.

A random number generator is a computer programme that constantly and rapidly creates new, random combinations of the available symbols to ensure that the game stays unpredictable. When you hit spin – or, on some games, use the auto-stop feature – the machine locks onto whatever combination the computer has created at that exact millisecond.

Why Do Online Casinos Use RNGs?

What is a random number generator used for? Well, if players simply knew which numbers were going to come up next, there wouldn’t be much point to the game. Casino games, like lotteries, are not supposed to be games of skill but, rather, games of chance. Otherwise, the casino may as well just give money away to any player who signs up.

Meanwhile, if the casino were to use a number generator that was not random, it would be possible for them to cheat players or for players to figure out the pattern and beat the system.

RNGs ensure that nobody, including the casino, knows which combination will land next.

Is It Possible to Beat the System?


There are a number of myths surrounding RNGs and that’s because many players have never gotten a proper answer to the question: “what is a random number generator?” People believe that it is possible to identify some sort of pattern in the RNG and so predict outcomes.

For example, people believe that a combination is less likely to come up if it has come up recently. The problem with this logic is that it assumes that numbers are event-dependent in the same way that card games are because each card can only come up once. With RNGs, however, the same number could theoretically come up again and again, ad infinitum. Each combination is completely independent of those that come before and after it. No pattern.

This also prevents sites from cheating players, which is why they tend to advertise the legitimacy of their RNGs very prominently. In order to prove that their RNGs are 100% random, casinos submit to tests by the Casino Control board and other authorities.