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Random Number Generator In Online Casinos

Posted on: October 26, 2023. Last updated on: February 14, 2024 RNG

One crucial aspect of all online casinos is transparency and fairness. That’s why we’ll discuss the technology that ensures the integrity of any gambling site – the RNGs. In this article, we’ll inform you about Random Number Generators, how they work, and what are their main types. You’ll also learn more about why casinos need them, which games rely on them, and the future of this technology in online gambling.

What Is A Random Number Generator & Why It’s Important

A Random Number Generator, also known as RNG, is a mathematical tool that’s designed to produce a specific sequence of numbers or symbols. As its name suggests, this specific string is original every time and practically unpredictable.

In the context of online casinos and gambling, RNGs are a system employed by all gambling sites to mimic this randomness of real-life actions like:

  • Spinning your game slot reels
  • Shuffling poker cards
  • Rotating a roulette wheel

This type of technology is what revolutionized our current online casino industry, allowing it to be impartial and ensuring players fair and transparent gaming conditions.

RNGs: Two Main Types

While Random Number Generators may sound simple, they’re not. Below, you’ll find more about the two types of RNGs and why they’re different:

Pseudorandom Number Generators Or PRNGs

This RNG type does not require any external input to produce numbers. It operates on an interesting principle where a seed of digits is fed to a series of algorithms that keep changing it.

While the name of this RNG may suggest that it’s not entirely a random one, that’s not correct. This Pseudorandom Number Generator requires only a seed, which makes it produce sequences that are unpredictable due to a constant change of all algorithms. PRGNs are often used in online casino sites because they’re reliable and extremely efficient.

Hardware Random Number Generators Or HRNGs

Unlike the Pseudorandom Number Generators, the HRNGs derive their randomness factor from physical processes, which makes them truly unpredictable. This type of RNG is often called a True Random Number Generator, as it can be based on phenomena like radioactive decay or thermal noise.

Such RNGs are less common in online casinos purely because of their costs. Hardware Random Number Generators are pricey because of being complex, and they are frequently used only in high-quality tournaments or games with incredibly high stakes.

However, that’s by far not all RNGs. To illustrate it, we’ve prepared a table listing some of the Random Number Generator types over the years.

NameYearInventorRNG Type
Middle-square method1946J. von NeumannPRGN
Lehmer generator1951D. H. LehmerPRGN
Linear congruential generator (LCG)1958W. E. Thomson; A. RotenbergPRGN
Wichmann–Hill generator1982B. A. Wichmann and D. I. HillPRGN
Rule 301983S. WolframPRGN
ACORN generator1989R. S. WikramaratnaPRGN
MIXMAX generator1991G. K. Savvidy and N. G. Ter-Arutyunyan-SavvidyPRGN
Xorshift2003George MarsagliaPRGN
Advanced Randomization System (ARS)2011J. Salmon, M. Moraes, R. Dror and D. ShawPRGN

To represent how RNGs operate, we’ll use one of the oldest types – LCG, as an example with its formula:

Xn+1​=(aXn​+c) mod m

Why Do Online Gambling Sites Implement RNGs?

Unlike land-based casinos, which have their own methods to ensure that a game is fair and random, online casino sites heavily rely on RNGs. That’s because digital gambling is rarely related to real-life croupiers, and it’s much harder to ensure fair gameplay.

For example, when you play a slot game or a round of online blackjack, the RNG is continuously producing new seed numbers. This replaces live dealer and slot machine mechanisms alike and ensures that every spin or deal is fairly processed through an RNG algorithm to determine the game outcome. This creates an independent environment where no previous result influences the following ones, allowing players to enjoy a fair game.

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Which Games Operate Based On RNGs?

Almost any virtual casino game without a live dealer relies on RNGs, from the standard 5-reel slot machine, where each reel has its value, to all popular card games like video poker, baccarat, blackjack, etc.

RNGs are used in table games like Roulette, Sic Bo, or TV show titles. In these games, be it a spinning ball, wheel, or dice, RNGs decide the landing, even though it may seem like a purely chance-based title.

Live Dealer Games: Are They Random Too?

Live casino games, which have gained huge popularity in online gambling, might raise many questions about their fairness and randomness. These games usually involve real dealers and are conducted over a stream, which implies that all random factors are executed by actual mechanisms and dealers rather than RNGs. These include several card decks, shuffling off the screen to ensure fairness, and even advanced tech like OCR (Optical Character Recognition) to read card values. All of these measurements suggest that live casino games do not utilize RNGs and rather rely on these practices to create a fair gaming environment.

Random Number Generators: Technology Ensuring Casino Integrity

To ensure the integrity of RNGs, many online casinos in Canada and over the world utilize third-party testing. These rigorous procedures are performed by international organizations like eCOGRA, Gaming Labs International, or QUINEL. The purpose of this action is to verify that gamblers are guaranteed fair gameplay thanks to these RNGs. Therefore, these authorities test and issue certificates that build trust among players, as their mark signifies an honest and not rigged gaming experience.

Online Casinos & RNGs In The Future

With online gambling getting more popular over time, RNGs are unlikely to disappear. With the continuous evolution of technology, the sophistication of Random Number Generators is imminent. We can expect better software and more complex algorithms that will easily guarantee a far bigger number of combinations.

Another aspect that may improve is augmented reality, where Random Number Generators will be even more crucial to ensure a fair and transparent gaming reality rivalling land-based casinos.


RNGs and all of its variants are the backbone of the online gambling industry. They ensure that every spin, roll, and deal is random and fair for all players with no predictability chance. As this exciting technology keeps advancing, we can likely expect even better RNG algorithms and software to develop. This will eventually lead to an enhanced trust in online casinos, which will be required for the jump to augmented reality gambling sites. The importance of RNGs will only evolve in the upcoming years, both for seasoned and casual players.

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