The Role of RNGs in Online Casino Games

Online casinos allow you to enjoy your favourite game while you’re at home. Basically, you’re sitting in front of your computer, playing a slot or a table game, and you start spinning the reels or the wheel. While it’s spinning, the thrill and the excitement increase, and finally, the symbols stop. So, have you ever wondered how casinos determine this outcome?

This is where random number generators, or RNGs, come into play. In fact, they produce numbers that correspond to the symbols on the virtual reel of the slot machine or the table game display. However, the biggest concern is how fair this is. Don’t worry! One of the primary uses of these computers is for casinos to ensure fairness regardless of who plays a particular game. 

So, if you want to learn more about the random number generators and discover additional information about their role in the casino industry, check out our detailed guide!

Random Number Generators (RNGs) Explained

The random number generator, also known as the RNG algorithm, is used by casinos to guarantee fair play and transparency in online games. More precisely, this system is not biased, meaning it provides fair outcomes by generating random numbers or symbols for every player. But how exactly does it work?

As we mentioned, RNGs depict the outcome of the gambling action. In other words, each game has a map of the numbers. Once the outcome is mapped, the screen displays the result of the spin. This system is not very exciting by itself, which is why many of the popular casino game developers, such as Microgaming, NetEnt, Pragmatic Play, and many others, combine it with thrilling features. 

That’s why the newer slots, for example, come with amusing features, such as cascading symbols, sticky wilds, free spins, and additional functionalities that add more excitement and keep you engaged. Having this in mind, we can indeed say that many factors influence the RNG outcomes of casino games, making your overall experience way more interesting.

How Do RNGs Ensure Fairness?

So far, we’ve explained what RNGs are and how they work. But let’s focus a bit on the transparency and the fairness part. In order to provide all of their loyal casino enthusiasts with a fair game, casinos generally use one of two types of random number generators – TRNGs (true random number generators), or PRNGs (pseudo-random number generators).

Let’s start off with the true random number generators. TRNGs act like extremely precise measuring tools. Basically, they capture all the unpredictable events in the game and turn them into random numbers. However, there is one issue. This algorithm is highly secure, which makes it expensive for casinos to use it very often. 

On the other hand, pseudo-random number generators are like advanced calculators. PRNGs use complex formulas that constantly change the initial number (something like a secret password) so they can create long lists of random numbers. From this arises the issue of repetitive lists. 

Luckily, online casinos have found a way to prevent predictability by leaving them always running, even if no one is playing at the moment. So, when you hit “start,” the last number on the list, i.e., the next spin of the slot or the next card in the deck, determines your game’s outcome. 

Casino Games that Use Random Number Generators

After understanding what RNGs are and how they ensure the game is fair, we should make it clear that almost all types of online casino games use them. Let’s briefly have a look at the list of games before we provide more details:

  • Slot machines
  • Table games
  • Poker
  • Craps
  • Keno
  • Scratch cards
  • Crash games
  • Lotteries and bingo

Although all of these games use the RNG algorithm, all of them use it differently. For instance, online casinos use it for card games in order to map out the order of the cards in the deck, which means the algorithm shuffles the cards. 

More so, casinos use it as a system that lists all possible combinations of numbers from the limited pool in bingo and keno. Ultimately, slots and scratch cards use it similarly because they both run on symbols and their board position. So, the generated number just outlines the position of those symbols. 

Random Number Generators and Online Casino Games

We have already briefly mentioned how RNGs work with some online casino games. But let’s go more in-depth into some of the most popular games – slots and live games. 

RNGs and Slot Machines

Above, we explained that RNG in slot games constantly works. However, the machine maps out and displays the outcome only when you press the spin button. But online games have their own perks. As the reels are virtual, the developers can fit in as many symbols as they prefer. This increases your chances of winning. 

For example, if you have a slot machine with three reels that have seven symbols and only one pay line, the number of winning combinations is significantly lower. Hypothetically, if each symbol is a number, the RNG will need to create a result in the range from 111 to 777. 

In contrast, modern slots have a lot of empty positions and symbols that aren’t only plain numbers but also have various functions. They even have numerous pay lines, measuring the number of possible outcomes in millions. Still, all of the potential wins are pre-determined and pre-mapped, which means that you won’t be able to cheat.

The fairness of RNGs goes so far that even if the slot has a hold-and-spin feature, you won’t be able to impact the outcome. The only thing you can affect is the speed at which the reel will stop. Still, the machine will display the final result as soon as you press the button. 

Last but not least, slot RNGs use the same algorithm for both base and bonus rounds. Once again, the result will be the same regardless of your chosen option. 

RNGs and Live Casino Games

While almost all online casino games implement RNGs, they are not necessary for live dealer games. This is because everything is done manually in such games using a real deck of cards, roulette wheel, or dice. 

You can find out the latest game reviews and see that other players are always aware of what the dealer is doing. On top of that, the studios employ multi-camera views, allowing you to monitor what’s happening throughout the whole live action. 

In order to understand better why live games don’t rely on RNGs, picture it like this. You play poker, baccarat, and blackjack with six or more decks of cards, which the dealer doesn’t reshuffle after each round. However, this makes card-counting strategies possible because the cards that the players have already drawn are no longer in the deck. 

Myths About Random Number Generators

Online casinos make sure to implement the best strategy in order to stay fair. They make sure their RNG algorithms are reliable, and they even conduct audits to prove their credibility. Still, some players believe that RNGs are not entirely fair. Let’s go over the most common RNG misconceptions together:

  • Online casinos manipulate RNGs
  • You can predict RNGs
  • RNGs provide only high or low outcomes

Tips to Stay Safe

If the above-mentioned issues concern you as well, we have a few practical tips that will help you relax and enjoy your online experience:

  • Play at online casinos with excellent reputation
  • Set a budget and stick to it
  • Avoid chasing your losses


Online casinos rely on random number generators to ensure a fair gambling environment. These algorithms generate entirely random, unpredictable, and non-manipulative results. The best part is that all types of casino games can use them, except for the live dealer ones. 

Despite all of the scepticism and low trust in these systems, their role is straightforward – RNGs make sure that each win you receive is entirely fair and doesn’t discriminate against any players.