All About the RNG (random number generator)

Jenn Clarke
Jenn ClarkeNovember 30, 2021
All About the RNG (random number generator)
clock icon Reading: 5 minutes

A random number generator also referred to as the RNG, is essential to the online gambling industry. It is how providers and operators ensure fairplay when games are accessed. When an RNG is used, the handling of cards, the actions at tables, and spins on slots are all controlled by a computer and a mathematical formula is used to make sure that all results are random. The RNG used at online casinos will also allow developers to set the payout percentages that are featured on supported games.

As soon as a game is started or reels are spun, the RNG is triggered and will produce a result that cannot be predicted. This ensures that every player has the same chances at winning and prevents any tampering with outcomes.

Why Online Casinos Use RNGs

When random number generators first started to be used, they were considered a new and improved way to run slot games. Before, slots would rely on the use of physical reels that would determine hat symbols would appear. Today, slot games featured online are much more complicated and are controlled by computers instead of physical reels. The use of an RNG allows developers to create more unique and innovative games while making sure they all operate fairly and honestly.

With slot games, strings of random numbers are created as soon as the game loads. There are sequences that are always moving and these do not stop until the spin button is clicked. At this time, the sequence halts and the RNG converts the sequence into an outcome. To maintain fairness, the best US online casinos will always test the RNG by using independent companies that audit games, such as iTech Labs.

What Games Use an RNG?

When you access an online casino, you will find hundreds of games that are supported. Any game that is part of the standard selection will be controlled by a random number generator. This will not matter what provider is used to power the site. All of the developers in the industry create their games using an RNG to ensure fairness. This means that you will find this in use when playing slots, blackjack, roulette, poker, and video poker games.

The only time an RNG is not used is when accessing live dealer selections. These games use human dealers and croupiers and the game is streamed from land locations. Since real dealers are controlling the games and the cards being used, an RNG is not in use. Instead, live dealer games will use the same technology and techniques used on a land casino to ensure a random result with each game that is played.

One thing to note is that live games will shuffle decks after every hand that is played. This is done to prevent card counting, especially when playing blackjack and baccarat games. The results remain random but are not as random as they could be when using an RNG.


When an RNG is used it will select certain combinations that will help to achieve a consistent RTP. Online casinos are legally required to monitor the RTP of every game that is supported to make sure that the RNG in use is not faulty in any way. Over time, online casino games will payout certain amounts at different rates, which is why the RTP is called a theoretical RTP. There are also true RTPs that are published by casino sites. You will find the best sites will use an RNG that offers similar theoretical and true RTPs.

Back to overview
Author Jenn Clarke

Jenn began an exciting journey in the iGaming industry more than 10 years ago as a content writer for various online affiliate sites, among these CasinoVibez. With a growing passion for gaming and an interest in the legal lands... Read more about the author

CasinoVibez » News » All About the RNG (random number generator)
Last updated: March 16, 2022