How does a random number generator work in a casino?


All online casinos use random number generators or RNG for short to determine the outcome of their games. This technology is most often found in slot machines, but it is also used for table games, scratch cards, and other games. First, it’s important to clarify the term “random” before we start talking about the random number generator. Randomness means that it is impossible or very difficult to predict in advance what the outcome of a particular action will be. In the case of casino games, this is, for example, a prediction of the next card that will appear on the table, or symbols for a spin in a video slot.

How the random number generator works and their types

Online gambling clubs, as well as video openings in a real club, use random number generators to get the most arbitrary result. The RNG can be software or potentially hardware.

A hardware-controlled RNG works by taking into account certain external factors when determining a random sequence of numbers. This can be, for example, temperature, atmospheric pressure, or the amount of a substance in the air. This factor yields a series of binary numbers that are converted by an algorithm into a specific move or card in a casino game. This is an optimally randomized method because it cannot be influenced and the factor is always different.

In addition, it is almost impossible to hack or hack a hardware RNG. This is because, firstly, the factor or factors being measured are often secret. Secondly, it is impossible to know, for example, the amount of carbon in the data center of an online casino at a certain time. Thirdly, the correct algorithm and operation of this sequence has yet to be discovered before a move, outcome, or card can be predicted. The disadvantage of a hardware RNG is that it takes longer to process and is therefore slower.


The random number generator also ensures that the probability of winning is the same in every game round. For example, if you just finished the free spins bonus round, the chances of the next spin triggering another free spins round are the same as after a hundred spins. In many ways, an RNG works like throwing a die. For each roll, the chances of getting a six are the same, no matter what happened on the last roll.

Even though the games themselves are fair, you should always remember that they are fair in the sense that they work as intended. That being said, the slot machine is never designed to pay out all the bets it receives as a win, since the RTP is set at less than 100%. After all, the casino must also earn somehow. So in terms of slots, what it means to be fair in the sense of fair play is that you are not at a disadvantage compared to other players. But you will be at a disadvantage compared to the casino. This is why cashing out big wins is so important.

What is a pseudo-random number generator?

The pseudo-random number generator works through software and therefore cannot measure external factors and include them in the issuance of a random result. Pseudo RNG is embedded, for example, in a microcircuit and contains an algorithm that gives a certain result at certain points in time based on a key or initial value. Since this software is not tied to an external factor, it can produce the most random result of a casino game much faster. However, an internal factor, such as hours, can be used.

A software random number generator is based on a key value. When one knows this key value, one can predict the outcome at a certain time. The fact that it has some form of reproducibility is not necessarily a disadvantage in the case of casino games, unless hackers take advantage of it. Due to the much higher speed and the fact that no additional equipment needs to be built into the video slot, for example, pseudo RNGs are widely used in casinos, both online and offline.


How do casinos provide random results?

There are several ways in which online and land-based casinos provide randomness. In board games, this can be done, for example, by manually shuffling the cards or by using a shuffling machine. This machine is designed in such a way that the cards come out randomly. According to statistical research, you should use “shuffling” seven or more times, or spread the cards on the table and shuffle them together for about a minute.

In both online casinos and land-based casinos, only live casino games work with manual randomness. The rest of the available casino games are powered by a (pseudo) random number generator. How it works is different for every game and every game developer or online casino.