Random Number Generators in Online Casinos

Have you ever heard of the idea that online gambling is legit because the results of the games are random? Well, what you heard is wrong – the games are not random. As the demand for online gaming increases at a staggering rate, games developers bend over backward to continuously improve their offering. Although casino games are becoming more intuitive with visual-stunning graphics that we have never seen before, one element remains the same. It is the Random Number Generator (RNG), the backbone of every game and the mechanism behind the result of each game.

What is a Random Number Generator?

A random number generator is a computer programme that generates a sequence of random numbers using mathematical algorithms. The numbers are expected not to be linked in any way that could be recognised. In other words, no patterns should be observed. It is not difficult to spot randomness in nature, but is it possible for a human-made programme to create it? The answer is no. Producing random numbers is the duty of RNGs; however, no human-engineered programmes are genuinely random. This is the reason why we mentioned above that there is no randomness in online casino games.

An RNG is not random as it is instructed to follow particular patterns. For instance, when an RNG is fed a random number (seed number), it should multiply the number by itself and use the middle of the result as the next seed to repeat the algorithm. Since mathematical operations have nothing to do with randomness – one plus one always equals two – a particular input will always generate the same output. Therefore some say that you can technically hack an RNG if you manage to find out what the seed number is.

How are RNGs Incorporated into Casinos?

What we described in the last paragraph is a pseudo-RNG, which is commonly used in online casinos. All it needs to work is an algorithm and seed number, which is why pseudo RNGs are also known as software RNGs.

Pseudo RNGs are used for games with no dealers. They are not only used in online casinos but also land-based casinos, especially for virtual games such as blackjack, roulette, keno, video poker, and video slot machines.

How do RNGs Work on Slot Games?

Slot games perfectly demonstrate how an RNG spits random numbers at an impressive speed. Let’s take a 5-reel slot with 12 symbols on each reel as an example. In that very microsecond when the player has pressed the “spin” button, the RNG will select a value of 1-12 for each of the five reels, resulting in 5 different symbols. If those five symbols form a winning combination, the player will receive winnings accordingly.

Then why is it so rare for players to hit the jackpot? This is because each number the RNG generates is connected to a specific symbol on the reel. It is reasonable that more numbers are linked to common symbols while fewer numbers are mapped to the jackpot symbol. Not to mention regular symbols take up the majority, whereas there is probably only one jackpot symbol on each reel.

Are RNGs Fair?

You shouldn’t worry about the fairness of RNGs if the casino of your choice is secure and reputable. Established casinos are regularly tested by third-party organisations such as Technical Systems Testing (TST), which provides a complete range of testing and consulting to both online and land-based casinos.

When a casino passes the tests, it means the games it offers are not influenced by external variables including size of the potential payoff and the number of credits in play. It also reflects that the games have achieved the minimum payout percentages required by local regulators. For example, the American state of New Jersey requires gambling operators to pay back 83% of the money that cycles through.

Dodgy casino sites with RNGs that are not random do exist, but it wouldn’t happen at the reputable online casinos we recommend at SmartphoneCasinos.

Can you Cheat RNGs?

Theoretically speaking, you can cheat RNGs, but it would require so much time and effort that most of us wouldn’t be capable of doing it. It is going to take billions of instances for a pattern to be spotted, and even if you manage to capture the pattern, it would only be a general guideline. On top of that, most RNGs have undergone vigorous testing during production as well as before their official releases. Leading games providers are successful for a reason: their games cannot be easily manipulated to pay out more than they intend to!


Despite the rumours about casinos trying to manipulate the outcome of RNGs or players who have successfully hacked the programme for a shortcut to a big win, RNGs used in regulated casinos are safe, reliable and fair. They have been strictly tested before officially launched and are regularly monitored by independent third-party agencies. Nevertheless, RNGs featured in unregulated casinos are not guaranteed to be fair, so make sure the casino of your choice is licensed by your local gaming regulator, for example, the UK Gambling Commission. With so many regulated casinos available, you must be able to find something that suits your needs!