In online casinos, a random number generator is a computer program that produces a sequence of numbers or symbols that cannot reasonably be predicted better than by random chance. RNGs are the backbone of online slot machines, virtual table games, video poker, and more. Each number generated is completely independent of the numbers before it. Just like a coin flip has a 50/50 chance of landing on heads or tails regardless of previous flips, each Spin on a slot machine has the same odds every time, unaffected by previous spins.

How do casino game RNGs work?

Online casino RNGs are typically pseudo-random number generators (PRNGs). PRNGs use a seed value and an algorithm to generate a sequence of numbers that approximates random numbers’ properties. The seed value initialises the PRNG, and the algorithm uses that seed to generate the sequence.

For an online slot machine, the RNG constantly generates random numbers, even when the game is not being played. Each of those numbers corresponds to a specific set of symbols on the reels. When a player clicks Spin, the game takes the latest random number and maps it to reel positions. The spinning animation is just for show – the outcome is already determined by the RNG the instant the player clicks.

Other casino games use RNGs in different ways, but the core concept is the same. RNGs determine the shuffle of a deck of cards in virtual blackjack or the roll of the dice in online craps. Every game outcome is the product of RNG numbers. If you need some additional information about RNG’s work, check out her latest blog.

RNGs and game fairness

Properly functioning RNGs are essential for maintaining online casino integrity and fairness. Players need to trust that game outcomes are genuinely random and not manipulated in the casino’s favour. Reputable online casinos use RNGs rigorously tested and certified by independent third-party auditors. These audits verify that the RNG is indeed random and hasn’t been tampered with. Online casinos often publish information about RNG certifications on their websites.

It’s critical to note that just because a game is RNG-based doesn’t mean you’ll win as often as you lose. Every casino game has a built-in house edge that gives the casino a long-term statistical advantage. The role of the RNG is to ensure that edge is consistently applied and game outcomes are random, not to make games 50/50 propositions.

Can players beat RNGs?

Because RNGs are fundamentally random, players can’t predict upcoming results or identify patterns that provide an edge. Strategies that involve tracking previous outcomes, like writing down slot spin results or looking at roulette hit histories, don’t work. The reality is that all casino gambling games are pure chance games. While you may be on lucky winning streaks or hit a big jackpot in the short term, you’ll always face the house edge eventually. RNGs ensure those odds are the same for every player every time.