How RNG's (Random Number Generators) Work – Understanding RNG's

after they leave a machine and someone hits a jackpot at the same location a short time later. It's easy to see why someone would feel this way, but it's simply not true, because the outcome of each spin on a modern slot machine is controlled by a random number generator, or RNG. An RNG is a powerful mathematical algorithm designed to constantly run through sequences of numbers. In the slot machine example, each number in the sequence is linked to a specific combination of symbols on the reels.

When someone hits the “Spin” button or pulls the handle on the slot machine, the RNG instantly picks the current number in its sequence, determining the result of the spin. Because the RNG is always working, another player would have to hit the button at the exact millisecond to produce the same result – which is why the idea that someone could “take” a jackpot is incorrect. In online casinos, slots spins are controlled by RNG's in exactly the same manner.

Online casinos also use RNG's for things that would be determined by cards, dice or other props in physical casinos. For example, a blackjack game played online uses an RNG to simulate one or more 52-card decks to decide what cards the players and dealer draw, though in that case the entire sequence of cards in the shoe is determined when the cards are virtually shuffled. The entire foundation of online gambling is based on RNG's, and it's probably correct to say that the industry would not exist without them.

Experts in the field of mathematics sometimes point out that the algorithms used by an RNG don't meet the absolute textbook definition of the word “random,” though there are tests that can determine whether they are random enough for practical purposes, of which online gaming is a big one. With that in mind, online casinos are subjected to regular tests as part of their licensing processes to ensure that their RNG's meet these criteria. Not all online casinos use the same software or algorithms to power their RNG's, but all reputable sites can produce proof or answer questions about the RNG's they use if asked.