When the question is "What is a random number generator?", the figure quoted most often is return to player, and read alone it tells a player very little. It describes how much a game pays back across millions of rounds, so a slot listed at 96 percent keeps four of every hundred units staked over that span. It says nothing about a single session.
Volatility describes how a game spreads its payouts over time. Two slots with the same return can behave in opposite ways: one pays small amounts often, while the other pays almost nothing for a long stretch and then pays a large sum at once. This measure is rarely printed next to the return figure. Some providers rate it on a scale inside the info panel, and reviews often estimate it from a short test, which is too few spins to judge.
The stated return is reached only over a volume of play that no person will ever sit through. Across an hour at one machine, the result depends on variance far more than on the average. A player can end far ahead or lose a whole budget on a game with a fair return, and both outcomes are normal. The percentage describes the design of the game over its whole life, and a single session sits somewhere inside that spread.
Reputable providers publish the return range of each title and send their random number generators to an independent audit lab. The certificate names the game, the version tested and the date of the test. A licence usually obliges the operator to offer certified games only, which is a real constraint on what can be installed. The same licence rarely requires the figure to appear on the game screen, so the certificate and the info panel remain the places to confirm it.
Part of every stake funds a prize very few players ever win, so the everyday return an ordinary player sees sits below the published figure even when that figure is accurate.
Yes. Many titles are released in several versions chosen by the operator, and the gap between the highest and lowest can reach several percentage points with identical graphics.
The certificate names the game, the version tested and the date of the test, confirming that its random number generator was checked by an independent laboratory.
Where available, the history lists recent rounds with their stakes and results, useful for checking a session; a handful of rounds proves nothing about the long term payback.
Some do. Where a game limits what one spin may pay, its rules state the ceiling, which trims the very top of the possible payouts.
The game's own information panel states the return for the copy in front of the player, and it is the only reliable place to read it before staking.