RNG Random Number Generator
The random number generator that decides the result of every slot spin. Each spin is independent of previous results, and testing labs such as GLI, eCOGRA and BMM verify its fairness.
| English | Random Number Generator |
|---|---|
| Classification | Math & Probability |
| English | Random Number Generator |
| Category | Math & Probability |
| Role | Determines every spin result |
| Characteristics | Independent each spin, no patterns |
| Testing labs | GLI, eCOGRA, BMM, QUINEL, iTech Labs, Gaming Associates |
| Related standard | GLI-19 (online gaming system standard) |
Overview
The RNG (Random Number Generator) is the program that randomly decides the result of every slot spin. The moment you press the spin button, the number the RNG produces decides where each reel will stop, and the reel animation on screen is just a presentation of a result that has already been decided.
Online slots use a “pseudorandom number generator (PRNG),” which creates random numbers with a computer algorithm. Although it is an algorithm, it is designed so results cannot be predicted, and it must be certified by an independent testing lab before it can launch in a regulated market.
Core principles of the RNG
Every spin is independent
RNG results have nothing to do with previous spins. A long stretch without wins doesn’t raise the chance of winning on the next spin, and a big win just now doesn’t lower the next probability either.
Unpredictable
Results must have no pattern, and the next value must not be predictable or manipulable from outside. That’s why testing bodies even check how the initial value (seed) is generated.
Follows the designed probabilities exactly
The RNG picks results randomly, but how often each result appears follows the game’s math design (paytable, symbol layout). That’s why, over the long run, RTP and hit rate converge to the designed values.
RNG certification process
Testing lab eCOGRA states that its RNG certification checks the following.
| Test items | Details |
|---|---|
| Source code review | Checking that the RNG algorithm is designed to meet industry standards |
| Statistical analysis | Testing with large amounts of data that the generated numbers are evenly distributed and have no pattern |
| Seed generation assessment | Checks that the initial values are generated in an unpredictable way |
| Security testing | Checking that it withstands attacks that try to predict or manipulate results |
| Environment assessment | Checks that the hardware and software environment does not affect RNG performance |
| Regular audits | Periodically checks that the RNG keeps working consistently and has not changed after certification |
GLI receives a game’s source code and math documents and simulates billions of games to verify that the RNG and RTP work as designed. For online game systems, it operates the GLI-19 standard.
Major testing labs
| Agency | Certification cases on this wiki |
|---|---|
| GLI (Gaming Laboratories International) | All CQ9 games, Betsoft, Playson |
| BMM Testlabs | PG Soft, Spinomenal, Playson |
| QUINEL | Thunderkick, Booongo, Betsoft |
| iTech Labs | Booongo |
| Gaming Associates | PG Soft |
| eCOGRA | Operates RTP and RNG certification services |
Common misconceptions
- “It hasn’t hit for a while, so it’s due soon”: Each spin is independent, so earlier results don’t affect the next probability.
- “Wins come more often at certain times of day”: The RNG works with the same probability regardless of the time of day.
- “I just barely missed, so the next one will hit”: A near miss is also just a random result decided by the RNG and has nothing to do with the next spin.
- “The demo and the real game have different odds”: The official demo provided by the game’s provider usually runs the same game with virtual credits. However, the real game’s RTP can differ depending on the RTP version the operator chooses.