How do random number generators work?
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A Random Number Generator (RNG) is a computer algorithm that produces sequences of numbers with no detectable pattern. In online casino games, RNGs determine the outcome of every spin, hand dealt, or dice roll.
How it works
Casino software uses what’s known as a Pseudo-Random Number Generator (PRNG). It starts from a seed value and runs it through a mathematical formula millions of times per second, producing a constant stream of numbers. Each number maps to a specific game outcome. The moment you click spin or deal, the system captures that instant’s number and converts it into the symbols on the reels or the cards in your hand.
Why results can’t be timed or predicted
The seed values change constantly and the algorithm runs too fast for any human to reliably time their action to a specific outcome. Even knowing the algorithm wouldn’t help since the current seed is unknown. This is what makes the results genuinely unpredictable from a player’s perspective.
How RNG certification works
Independent testing laboratories like eCOGRA, iTech Labs, and GLI audit casino RNGs by running tens of millions of simulated rounds and checking that the distribution of outcomes matches the game’s mathematical design. Regulators require this certification for a casino to maintain its operating license. All licensed casino games are built on certified RNG systems.
Ben Barber got into the gambling industry through the poker rooms of London in the early 2000s. After building up a solid grounding in casino, sports betting and poker, he made the move to Malta where he spent close to a decade writing for some of the biggest affiliate networks in the region. A few years ago he relocated to Bali, which shifted his focus toward website strategy and affiliate marketing. The casino side never really left, though. He still writes reviews, how-to guides and in-depth pieces on everything from slots and live dealer tables to crypto casinos and sweepstakes sites. His approach is fact-first: help players understand how online gambling actually works before they deposit a cent.