Fairness and RNG
A licensed game's results are random and its return is tested.
By Ryan Jessop. Last checked .
Key takeaways
- A random number generator decides each result.
- Games are tested before release.
- Operators monitor live returns.
- Fair does not mean you will win.
How an RNG works
It produces numbers continuously. When you press spin or deal, the game takes the number at that instant and maps it to an outcome. No result depends on the last.
Testing
Games offered in Britain must be tested by an approved test house, and operators must monitor live games against their expected return.
Live games
Real cards and wheels, in licensed studios, with shuffling machines, multiple cameras and audited equipment.
What fair means
That the game behaves as its rules and RTP say. The house edge is part of a fair game.
What you can check
- The casino's licence on the public register.
- The RTP in the game's help screen.
- The rules panel on a live table.
More guides: Games and bonuses, Bankroll guide and Casino games glossary.
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RTP settings
A casino choosing a lower RTP version of a slot is not cheating; it is a permitted setting, disclosed in the game. It is also a reason to read the help screen.
Go further: Slot paylines and ways UK, How to play baccarat and Multiplier roulette UK.
House edges and RTPs are standard published figures for common rules, and are long-run averages. Offer terms dated 5 October 2026. How we check. 18+. Free help: 0808 8020 133 or safer gambling.
Frequently asked questions
Are online casino games rigged?
Not at licensed casinos.
What is an RNG?
A random number generator.
Who tests games?
Approved test houses.
Does fair mean I can win?
Sometimes, and less than you stake on average.