A large part of the appeal of casino games is their unpredictable nature. Although each game has a house edge that ensures it wins in the long run, it is far from certain that a player will lose each and every time. Certain outcomes are more likely than others, but it is perfectly possible to win because each is entirely random.
In a land-based casino, most games are naturally random. For example, the particular compartment of a roulette wheel in which the ball ends up effectively comes down to physics. The same is true for what number shows after the roll of the dice. The order in which cards appear is randomized through shuffling.
Online casinos have to somehow replicate this natural randomness artificially in order to provide an experience as close as possible to a real casino. This is done through the use of random number generators (RNGs), which also help to ensure that the games are fair.
On this page we explain how these RNGs work and the benefits they provide to casinos and their players.
The games you play at online casinos are all powered by fairly hi-tech software. Regardless of which casino you play at, the software used will contain some programming code that continuously generates strings of random numbers. This code is essentially what constitutes an RNG.
Any time the software needs to produce a specific outcome, such as the result of a spin of a roulette wheel, it will use one of the randomly generated numbers to determine what it should be. This is a very simplified explanation of how things work, but it should give you the basic idea.
The code that generates the random numbers has to be very complicated. Strictly speaking, computers are not able to reproduce true randomness; there will always be some kind of pattern. By making the code complex enough, any pattern that develops should be unrecognizable.
Generally speaking, each number, or sequence of numbers, is influenced by what is known as a seed. The seed is also random, which ensures an RNG is sufficiently randomized to serve its required purpose.
Roulette wheels, decks of cards, and dice do not have memory. Each result is entirely independent of previous results. They will always produce the expected results in the long run because of the laws of probability, but there can be significant statistical variance short term.
For example, if you roll a dice 6 million times, you would expect to see each of the six numbers come up close to 1 million times. If you roll it just six times, however, it is far from certain you would see each come up once.
By using RNGs, casino software produces outcomes that are not based on previous ones, which is exactly how it is in a real casino. If black came up 6 times in a row on an online roulette wheel, it would no more or less be likely to come up black again on the next spin.
It's the random nature of casino games that causes statistical variance, which is what ultimately makes it possible to overcome the house edge short term and actually win money. Therefore, RNGs are entirely necessary for an online casino to provide a realistic experience.
RNGs not only ensure realistic games, but they also protect online casinos in a couple of ways. First, they make it possible for them to prove they are providing fair games. One of the biggest reasons why some people are put off playing online is a concern about fairness, and it is a quite common fear that online casinos in some way cheat players.
Most online casinos (and certainly the reputable ones) are licensed by a gaming authority. In order to maintain their license, they usually have to be subjected to a software audit by a third party. These software auditors test RNGs and make sure they are performing as they should. If a casino can demonstrate they are using an effective RNG in the correct way, this confirms that their games are fair.
Effective RNGs can also protect online casinos against being cheated themselves. As mentioned earlier, 100% randomness cannot be reproduced artificially, and some form of pattern will always develop. If a casino uses an RNG that is not randomizing sufficiently to make patterns unrecognizable, then it could possibly be exploited. Any player clever enough to spot a pattern could, theoretically, be able to predict the outcome of games. Such a scenario would obviously have the potential to be very expensive for an online casino.
Hopefully, it should now be clear what RNGs are, how they work, and why they are used. You don't really need to know any of this to enjoy playing at online casinos, but at the very least it may put your mind at ease if you have any concerns about whether they are fair.