Fairness and RNG Testing Methods
An explanation of how game outcomes are produced and how that process is checked from the outside. The page covers the role of the random number generator, what the return-to-player figure means, the points an independent test house examines and the checks that continue after release. It also explains what players can review in their own account.
Basic principle
Every outcome in the game library is produced without any influence from the operator, a member of staff or the player. Results are determined by a random number generator, which produces a value for each stake and converts it into symbols, cards or numbers. This principle applies to every title on offer, regardless of the stake or the time of day, and holds just as much for a 20p spin as for a £5 one.
How the generator works
The generator runs on the game supplier’s servers, not on the player’s device. It produces numbers continuously, even when nobody is playing, and the moment the spin button is pressed determines which value is used. Previous rounds play no part in this. A run of losses does not make a win more likely, and a large payout does not reduce the chance of the next one.
Return to player and variance
A game’s theoretical return to player is calculated over millions of rounds. At an RTP of 96%, a title returns an average of £96 for every £100 staked on that scale, with the difference kept by the operator. Over a half-hour session the figure says little, because results can vary widely around the average. High-volatility titles pay out rarely but in larger amounts, while low-volatility games return smaller sums at shorter intervals.
Independent testing
Before release, software is assessed by accredited test houses approved by the UK Gambling Commission, which have no ties to the game supplier or the operator. Testing is carried out against the Commission’s technical standards and covers, among other things, the following points:
- Statistical distribution: number sequences are run through chi-square and frequency tests on large samples.
- Unpredictability: the seed value must not be derivable from previous outcomes.
- Symbol frequency: every symbol and card must appear evenly across the full range.
- Payout: the actual return is compared with the published RTP.
- Source code: the game logic is reviewed line by line, including bonus rounds and free spins.
- Connection: traffic between the game server and the platform is checked for security.
After release
A certificate applies to one specific version of a game. If that version is changed, it is tested again before the title goes back live. Checksums of the game files are compared with the certified version at regular intervals, so any discrepancy becomes visible. Settings cannot be changed per player or per session, and the balance on an account has no effect on how a title behaves.
What players can check
The information screen of each title shows the RTP, the paytable and the rules for bonus features. The game history in the account lists the date, time, stake in pounds and outcome of every round. If a result is ever in doubt, the server logs are treated as the deciding evidence, because that data cannot be altered from the player’s device.
Live tables
Games with a real dealer do not use a random number generator. Outcomes there come from physical equipment such as card shufflers, wheels and balls, which are inspected and maintained at fixed intervals. Footage is recorded and stored, so any round can be reconstructed later. These tables are also reviewed by external parties, although the checks focus on procedures and equipment rather than software.
What this means for players
No betting sequence, pause or switch between titles changes the odds of an outcome. Demo versions show the same mechanics without using real money and are a useful way to learn the rules. Players who use the figures on this page as a reference play with a realistic view of what a game returns over the long term.
