Guide to Random Number Generators in Online Casinos

In our casino reviews, you will notice we always mention the casino’s fairness and transparency. Usually, one aspect pointed out as an indication that the casino is fair is that their random number generator, or RNG, is regularly checked by a third-party testing organization. So, what exactly is an RNG, how do online casinos use it, and is it really a reliable way to tell if a casino is trustworthy? Read on to find out all the answers as we explain in detail number generators and their significance to online casino sites. 

What Is a Random Number Generator?

As can be inferred by the name, a random number generator is a mathematical concept that is used to produce a single number or a string of numbers on demand, and in online casinos, it is meant to do so in order to replace the physical actions that randomize casino games, like the shuffling of cards or the rolling of dice, since the string of numbers can’t be predicted. 

For example, if you’re playing blackjack at a land-based casino with a single deck of 52 cards, the dealer will shuffle the deck, and the cards dealt to you from the top of the deck will be unknown to anybody. In order to ensure this randomness of online games, casinos use the RNG software that “shuffles” the cards instead of the dealer. 

The RNG that casinos utilize is a program code using the MD5 algorithm built into a casino’s software. By generating random numbers, it eliminates the possibility that the outcome of games can be tampered with or rigged. The RNG algorithm is able to avoid the repetition of a particular pattern and ensure random results every time by using mathematical equations and formulas. 

Types of Random Number Generators

RNG software has applications in a number of areas where an unpredictable result is needed, not only gambling. It can be used in any program that needs to generate random numbers or values, such as computer simulations, cryptography, and many more. There are different types of RNGs that, although aimed at achieving the same result – a random number or value, work in slightly different ways to accommodate this versatility. 

Pseudorandom Number Generator

This type of RNG can produce random numbers without the need for external numbers or data, as it uses a seed number to produce an output. The seed number is fed through a number of algorithms to produce the next number. Since these algorithms are fixed, the RNG is not truly random, hence the name pseudorandom. Although there is a finite number of algorithms, the pseudorandom number generator is able to produce new random number sequences all the time as the seed number comes with millions of digits after the decimal. It takes numerous mathematical operations to calculate the next value, which practically makes the outcome of the game unpredictable. 

Let’s look at an example of a pseudorandom number generator that produces numbers from 1 to 10. 

Pseudorandom Number Generator

1. We start with a number in this range, say 5. This number is called the seed number. 

2. In order to produce a random number, we take the seed and multiply it by 8. 

3. Then we take the result, divide it by 11, and take the remainder. That produces 7 – that is the random number. It is also the new seed, replacing the 5.

4. To generate another random number, we start with the 7, multiply it by 8, divide that result by 11 and take that remainder, which is a 1. 

We keep doing this every time we need a new random number. Now, the special numbers we used in the math – the 8 and the 11 have been chosen so they have certain mathematical characteristics and relationships with each other. We can choose different numbers if we want a different range of pseudorandom output.

Hardware Random Number Generator 

This type of RNG is a device that produces random numbers or values from a physical process rather than an algorithm. Hardware RNGs are also called True RNGs as they use processes that are considered completely unpredictable, such as thermal noise, for a starting point of the number generation process. 

How Online Casinos Use RNGs

RNG is not a new concept to casinos or something that is exclusively used in online casinos. In fact, land-based casinos. As we’ve progressed from mechanical slots, land-based casinos have been using hardware RNGs for quite some time. This generator is connected to the casino’s server through a USB point. Once a connection has been established, the device will use compound values from unstable atmospheric phenomena or physical processes as a starting point for developing a result of different games.

Online casinos use pseudorandom number generators for virtual games that are not hosted by a real dealer, i.e., there is no human input. Casino game developers incorporate this software in their games to ensure the randomness of each release. When you open a game at an online casino, the generator is already producing a new seed number every millisecond.

The online casinos use pseudorandom number generators

The moment you hit the button ‘Spin’ or ‘Deal’, a seed number is selected, and via the means of the algorithms, the next numbers are generated. All symbols in a slot game or cards in a card game are assigned a numeric value. The RNG communicates the numbers to the casino software, and thus, the outcome of the game is determined – the reels of the slot stop, cards are dealt, the dice is rolled, or the roulette ball lands in a pocket. 

Which Casino Games Use RNGs?

All kinds of virtual casino games can use RNG. It not only allows developers to introduce new mechanics and features to make the games more interesting, but it also helps them guarantee that their outcome is truly random. For example, with slots, each symbol on a reel is assigned a value. In a 5-reel slot machine where each reel has six symbols, the RNG will generate a value of 1 – 6 for each of the five reels.

In a card game like baccarat, one of the most widely used generators is Mersenne Twister which is usually utilized together with a Fisher-Yates shuffle, an algorithm that produces random ordering of a finite sequence, a deck of cards being one such sequence. As we mentioned earlier, each card is assigned a numeric value, and as random numbers are generated, they determine the outcome between Banker, Player, or Tie. 

Virtual casino games use random number generator

Randomness of Live Casino Games

We already mentioned that RNGs are used to ensure the randomness and fairness of virtual casino games, i.e., those games that are not hosted by a real dealer, so considering how popular live dealer games have become, you might be wondering what steps are taken to ensure they are not rigged. Well, pretty much the same way that land-based casinos ensure their games are fair. 

Many live casino games use RNG

Live dealer card games are played using at least six decks of cards, which significantly limits card counting possibilities. In addition, the shoes containing the decks are shuffled by casino staff different from the dealer, and there’s also a pit boss who, similarly to the ones in land-based casinos, oversees all operations and settles potential disputes. All games are streamed live and recorded, so there’s footage that can be used in dispute resolution. In addition, most live dealer studios offer multiple camera views so that players can keep tabs on all the action at the table. 

There are, however, options that combine the randomness of using RNG and the immersive experience of playing against a live dealer. Real Dealer Studios have developed a series of virtual games, including roulette and baccarat, in which RNGs are used to determine the outcome of the game. They also use prerecorded video of a real dealer to create an immersive experience as the dealer reacts to the gameplay, celebrating wins and commiserating losses. 

How Is the Fairness of RNGs Guaranteed?

 All reputable casinos submit their RNGs for independent third-party testing. A number of organizations are certified to test casino RNGs to ensure their randomness and fairness. Among them are names like eCOGRA, QUINEL, Gaming Labs International (GLI), Gaming Associates, and iTechLabs. 

Typically, RNG testing is carried out in three main stages: source code is compiled to evaluate the RNG algorithms and their implementation; the generated numbers undergo ‘diehard’ and other statistical tests; finally, a scaled output sample is generated sample, and more tests like ‘Chi-square’ are applied. Through this process, the testing organization looks to establish and assess the statistical randomness, non-repeatability, and unpredictability of RNGs. 

Organization Information Web
  • Operating since 2004
  • Certified over 300 RNGs in 15+ languages
  • Testing in Australia, Asia and Europe
  • Testing RNGs and live dealer studios
  • Ten years’ experience
  • Laboratories in Italy, Malta, UK and Argentina
Gaming Labs International (GLI)
  • Over 30 years’ experience
  • Locations on six continents
  • U.S. and international accreditations
Gaming Associates
  • Recognized Accredited Testing Facility (ATF) in almost all regulated markets
  • 30 years’ experience in the Internet gaming industry

RNGs Ensure a Safe and Fair Online Casino Experience

As you can see, RNGs are at the heart of casino operations. In addition to making gambling a safer and fairer practice, they have also created opportunities for game developers to release uniquely designed games that, regardless of the mechanics and gameplay, are guaranteed a random outcome every time. 

Now that you know why all casino reviews keep mentioning RNG testing, check out some of our recommended casinos that have been certified as fair and enjoy your favorite games safe in the knowledge that it’s fair and random.