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Random Number Generator
Find Everything About RNG in Online Casinos

Jacob Evans

Article by

31 Mar 2025

Random Number Generation has always been around, from a toss of a coin to any game of chance where the outcome can be random - whether computerised or manual. Only recently has it become an “IT” word due to the use of Computerised Random Number Generators (RNG) by Online Casinos!

So What is Random Number Generation?

It is a production of a completely random sequence of numbers or symbols without a pattern so cannot be guessed/predicted. In Casinos, to use their correct title, Pseudo-Random Number Generators are used to achieve this.

Mainly identified with one-armed bandits/slots/Fruit Machines RNG is used in all online casino games but are not purely assigned to gambling. They are found in online Gaming, such as Warcraft, where an outcome needs to be as random as possible or at a time an event has a chance of happening - injury, attack etc.

In online casinos, the use of RNG is for fairness and to ensure that both they and the gambler are not being cheated.

How Does an RNG Work?

So a series of random numbers or symbols are required, a simple task for a computer in this day and age… but believe it or not, they cannot. Computers use algorithms when a random outcome is required, the algorithms are extremely complicated but will need a starting number to proceed – this is called the “Seed” or “Seed Number”.

Once a new number is calculated that then can become the seed for the next set of numbers and so on and so on over and over. It is impossible to predict the next number in the sequence unless you know the original seed number. The normal execution uses a 32-bit word length allowing it to generate a number from 0 to over 4 billion (4,294,967,295 to be exact).

The numbers are massive, with standard RNG’s across the world working with random numbers that have 219,937 digits! If that was not mind-boggling enough imagine that the original seed number was also a random-generated one, how can you possibly predict what is up next! You may be asking that the dice has only has the numbers one to six, why is 219,937 digits needed? Such is the algorithm formula a random integer can correspond to a specific outcome i.e., final number of 1-6-12 .

The RNG

Is constantly producing a stream of completely random numbers that can be called on at any moment.

The Trigger

As soon as you click deal or spin, the RNG throws a random number at the game software.

The Outcome

The random number is then put through a game software to create a tangible result, like a dealt card or slot result.

How Can You Be Sure That You Are Not Being Cheated?

Your experiencing a losing streak or gambler’s fallacy – your head is telling you are being cheated so you try and observe a dealer’s sleight of hand or an uneven spin of the wheel. This is difficult in a brick and mortar casino -in the flesh- so how can you be sure that a RNG is not being manipulated when you could be halfway around the the world?

True in the early days of online casinos some were found guilty of rigging the RNG or the appearance of one, but also was the case of gamblers with inside knowledge. Let us put any fear you may have that the RNG is rigged to bed.

Online casinos today are tested and evaluated by 3rd Party companies who will then award their seal of approval, just ensure you check for the appropriate seals and authenticity before you start gambling. One Such third party company is Technical Systems Testing (TST) not just with Online casinos but brick and mortar too.

TST perform evaluations and audits on:

  • Random Number Generator (RNG)
  • Game and mathematics
  • Ongoing RNG or game payout verification and reporting
  • Live dealer casinos, sportsbook or betting exchange
  • Lottery and Pari-mutuel system
  • Poker system
  • Penetration testing and full security

Only when they are satisfied will a seal of approval be awarded/ renewed also look out for Gaming Laboratories International (GLI) who now own TST.

Main Seals of Approval and Official Registrations/Affiliations to Look For

e-Commerce and Online Gaming Regulation and Assurance (eCOGRA)

An internationally approved testing agency, player protection and standards organisation.

VeriSign

An Internet Security and Network infrastructure Company that issue trust seals for Casinos and e-commerce sites. They offer different services with one aspect ensuring that information held (including players, casino clients) is protected against hackers and cyber threats.

PricewaterhouseCoopers (PwC)

Have a World renown reputation in Audit and Assurance -which may have been dented somewhat with their involvement in the 2017 Oscar Best Picture Winner fiasco, when a partner reissued an already awarded envelope causing the incorrect winner to be announced.

Reputable Software Providers

Here listed are some of the Leading iGaming software designers/providers:

  • Net Entertainment (NetEnt)
  • Playtech
  • Microgaming
  • BetSoft

Reputable Live Dealer Gaming Manufacturers

The top two in this field are Evolution Gaming and Ezugi.

Online Gambling Jurisdictions & Licensing Authorities for the United Kingdom

The following are Internationally recognised as legitimate licensing authorities. They are included in the “white-list” issued by the United Kingdom Gambling Commission meaning they and their licensees adhere to the United Kingdom Gambling Act 2005:

  • Gibraltar
  • Alderney
  • the Isle of Man
  • Malta

Also included in the white list are EEA countries, Antigua and Barbuda, Tasmania. The White List was closed to new applicants in 2009. The Gambling Commission will be the authority for the United Kingdom-based casinos be it the traditional brick and mortar casino or the Online Variant.

Trusted Banking Methods

For example, the e-wallet PayPal who have their own strict guidelines that the casinos must adhere to for their affiliation.

RNG vs. Live Dealer Games

We believe RNG is the fairest and easiest way to gamble but may lack trust as the workings can not be seen as per a Live dealer/game. Live Dealer/Games come at more expense to the casinos so there is a limit to game types and styles, but in their defence, they are accessible 24/7.

RNG Virtual Games

Quicker deals – card games

Not rigged

Endless supply of games

New and innovative designs

No Interaction with virtual games

Computer environment

VS

Live Dealer Games

Interact with a real person

Actual gaming environment

Slower paced preferred by some

Human dealers can cheat

Limited games

Rarely a design change

It is down to personal preference whatever you decide, but in our opinion, nothing will beat the style and panache of a traditional brick and mortar casino, even though the most difficult option in this day and age.

FAQ

What is a Random Number Generator (RNG) and how is it used in online casinos?

A Random Number Generator (RNG) is a system that produces a sequence of numbers or symbols that cannot be reasonably predicted. Online casinos use RNGs to ensure fair play in their games. This means that the results of games like slots, roulette, or card games are completely random and not predetermined or manipulated.

How can I be sure that the RNG used by an online casino is fair?

Reputable online casinos have their RNGs tested and audited by independent third-party companies. These companies, like TST (Technical Systems Testing) or GLI (Gaming Laboratories International), specialize in evaluating the fairness and randomness of RNGs. Look for their seals of approval on the casino website to ensure the games are fair.

What is the difference between an RNG-based game and a live dealer game in an online casino?

RNG-based games use a computer program to generate the results, ensuring complete randomness. Live dealer games, on the other hand, involve a real human dealer who interacts with players in real-time via video stream. While both types of games can be fair, some players prefer the human element and interaction of live dealer games, while others appreciate the speed and efficiency of RNG-based games.

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Written by

Jacob Evans

I'm Jacob Evans, your go-to expert in online gambling. With a robust background in casino gaming and a knack for breaking down complex betting strategies, I’m here to guide you through online casinos, sharing tips to help novices and seasoned bettors excel.