What is an RNG at online casinos?
Bob Mitchell
Last Updated:
15 Dec 2024
The software that determines the outcome of every spin, card deal, or dice roll at an online casino. A certified RNG produces statistically random results that cannot be predicted or manipulated.
What an RNG is
Every game at a reputable online casino uses a random number generator to determine outcomes. The RNG is software that produces an enormous sequence of numbers at high speed, each one corresponding to a possible outcome in the game. When you spin a slot or draw a card, the RNG picks a number, and the game displays the result that number corresponds to.
A well-implemented RNG produces results that are statistically independent: the outcome of one spin has no influence on the next. This is what makes online casino games genuinely unpredictable on a spin-by-spin basis, regardless of what has happened in the previous rounds.
How RNGs are certified
Reputable game developers submit their RNG software to independent testing laboratories for certification. Organisations such as eCOGRA, iTech Labs, and GLI audit the software and confirm that it produces genuinely random results within the expected statistical parameters. The RTP of the game is tested and verified at the same time. A certified game will usually display the testing laboratory's logo in the game information panel.
Why it matters
An uncertified or poorly implemented RNG could produce results that are not truly random, potentially favouring the casino beyond the published house edge. This is why playing at casinos that use software from established, certified developers matters. The certification is not a formality; it is the mechanism that backs up the fairness claims.