RNG (random number generator)
An RNG, or random number generator, is the software that decides the outcome of every spin, card and roulette result in a digital casino game. At the moment a player presses spin, the game takes the latest number the generator has produced and maps it onto a symbol, a card or a pocket. The reels that follow are animation. The result was fixed before they started moving.
How a casino RNG produces a result
Almost every online game uses a pseudo-random generator, an algorithm that starts from a seed value and turns it into a long stream of numbers with no detectable pattern. Testing labs such as eCOGRA and GLI review the source code, check how the seed is created and run the output through statistical tests for uniform distribution.
Each result is independent of the last.
That independence is why a slot is never “due”: a jackpot on the previous spin leaves the odds on the next one exactly where they were, and a cold hour of play tells a player nothing about the hour that follows, however strongly it feels otherwise.
RNG compared with RTP
RNG is most often confused with RTP, the long-run percentage of stakes a game is designed to return. One decides each result; the other describes the average across millions of them.
RNG | RTP |
|---|---|
| Picks the outcome of each round | Describes the average return over many rounds |
| Says nothing about how much a game pays | Shows the house edge, e.g. 96% RTP means 4% |
| Audited by independent testing labs | Verified by labs against the paytable |
| Same certified generator across versions | Can differ between operators for one slot |
Where players meet the RNG
Slots, virtual blackjack, video poker and automated roulette all run on an RNG, while live casino tables use a real dealer and physical cards or wheels instead. What I check first on any game is the provider’s certificate, because RNG testing requirements are set by each licensing jurisdiction and practice varies between operators.
A certificate proves randomness, not generosity.
