How does rng work in online casino games?

Random number generation, or RNG, is a core component of many video games. But how does RNG work in online casino games? And what purpose do they serve in game development? This article will explore the inner workings of RNG and explain why it is one of the most important elements of casino game design.


Before we dive in and explore randomness in online casino games, let’s take a closer look at what RNG really is. There are two main categories of RNG: hardware RNG and software RNG. Hardware RNG is a physical device that generates random numbers. There are many different types of hardware RNG, but they all have one common goal: to generate random numbers. Random numbers can be used for various purposes, such as generating cryptographic keys, picking lottery numbers, simulating random events or determining which symbols will fall on the reels of your favourite slot. Hardware RNG can be divided into two main categories: true random number generators (TRNGs) and pseudo-random number generators (PRNGs).

Software RNG is a computer program that generates random numbers. There are several types of software RNGs as well; they are generally PRNGs, meaning that software RNG relies on algorithms to mimic the selection of a value to approximate true randomness. 


RNGs use a variety of algorithms to generate random numbers that are incorporated in online slot games. One RNG algorithm can be more sophisticated than the other, but all rely on a set of principles that ensure the resulting numbers are truly random. 

One such principle is called entropy. Entropy is a measure of how unpredictable a set of data is. The higher the entropy, the more random the data is. The RNG will draw from a data pool with high entropy to generate a random number. This pool is constantly refreshed, guaranteeing that the numbers generated are always new and unpredictable.

Another important principle is called seeding. Seeding ensures that each time the RNG generates a new set of numbers, it does so in a unique way. This prevents the same sequence of numbers from being generated twice. Using different seeds, RNGs can produce billions of unique sequences of numbers.

These principles are at the very core of casino game development, particularly when it comes to slots. RNGs guarantee that all outcomes of reel spins, digital dice rolls or card draws are randomised and unpredictable. This means that all players have an equal chance of winning — and losing. That is precisely why it’s important to only play at licensed online casinos that partner with licensed game providers. Operators and providers offering services under reputable licences guarantee that the games are safe and fair in every aspect. 


RTP (Return to Player) is a percentage value representing the theoretical return of an online casino game if played over infinite time. It is usually around 96-98% for most online slot games, for example. The rest is considered the casino’s income, as it compensates for any potential losses and covers all operating costs, such as staff salaries, RNG testing and other expenses. In online slots, the RTP is a statistical average obtained over millions of spins. This statistic is hardwired into the game, and providers must pass all audits and inspections that test the game’s fairness and RTP accuracy. This is where RNGs come into play, as they directly influence the randomness of all game outcomes, like the frequency and size of wins.

Similarly to the RTP, the house edge represents the casino’s advantage over the player in a given game. For example, an RTP of 98% is the same as a house edge of 2%; however, the house edge is often used in the context of live games like roulette and blackjack. In part, that’s because the house edge can increase or decrease in table and card games depending on the player’s in-game decisions. As more and more variants of these games pop up, you’ll notice that many providers will opt to express the house advantage as an RTP, particularly in regards to side bets. 


Along with online slots, RNG table games are another great example of random number generators in action. In Live Casino games, the live dealer generates all card draws, wheel spins, and dice rolls. On the other hand, RNG table games rely on the output of an algorithm. In a sense, you’re playing against the algorithm when you play at an RNG table.

The way these games work is that each RNG wheel spin or hand has its own, truly random seed and outcome: the RNG doesn’t “look ahead” to see what will happen next and adjust outputs accordingly. No matter how often you play roulette with the same bets, each wheel spin will be independent and unpredictable.

RNGs play a vital role in the design of every casino game. They are responsible for generating random numbers that can be used in various ways, from creating variability and unpredictability to simulating realistic gameplay. RNGs draw from their pool of high entropy data to generate each number, ensuring that the resulting sequence is both unpredictable and unique. By utilising different seeds, RNGs create countless possibilities for new sequences, meaning that every player stands an equal chance of winning.

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