Slot RNG Explained
How random number generators decide every spin, why each result is independent of the last and how games are tested for fairness.
Every pokie, whether it sits in a local club or runs on a phone, follows the same basic rules. A random number generator decides each result, a mathematical model sets how much the game pays back over time, and a set of features shapes how wins are formed and how bonus rounds play out.
These guides explain those rules in plain English. Each one focuses on a single topic, so you can read them in order as a short course or jump straight to the question you have in mind.
If you are new to pokies, we suggest reading these five guides first. Together, they cover the ideas that explain most of what happens on the reels.
These guides explain how results are decided and what the published numbers really mean.
How random number generators decide every spin, why each result is independent of the last and how games are tested for fairness.
What return to player measures, how it relates to the house edge and why many games are released with more than one RTP setting.
Why your results in a single session can be very different from a game's published RTP, and why RTP only becomes meaningful over a very large number of spins.
How volatility affects the size and frequency of wins, and how to recognise low, medium and high volatility games.
How progressive jackpots grow, the difference between standalone and linked jackpots, and how jackpot contributions affect a game's base RTP.
Common beliefs about "hot" and "cold" machines, near misses, timing and betting systems, and why they do not hold up.
These guides explain the different ways pokies turn symbols into wins.
How fixed and adjustable paylines work, and how the number of lines affects the cost of a spin.
How "243 ways" and similar systems pay for matching symbols on adjacent reels without fixed lines.
How reels that change size on every spin create a varying number of ways to win, and what that means for volatility.
How grid-based games pay for groups of matching symbols that touch, instead of lines across the reels.
How winning symbols are removed and replaced, allowing several wins from a single paid spin.
A step-by-step walkthrough of the paytable and game rules, including symbol values, feature triggers and the RTP shown for the version you are playing.
These guides explain the features that give each pokie its character.
The difference between low-paying and high-paying symbols, and the special symbols that trigger features.
How wilds substitute for other symbols, plus expanding, sticky, walking and multiplier wilds.
How scatters pay and trigger features wherever they land on the reels.
How free spins rounds are triggered and retriggered, and the extra features they often include. This guide covers free spins as a game feature, not casino bonus offers.
How multipliers increase wins, and the difference between fixed, random and progressive multipliers.
An overview of pick-and-click bonuses, hold-and-win features, wheel bonuses and other common bonus rounds.
How bonus buy features work, what they cost and why they increase the amount you have at risk.
How free-play demo versions work, what they are useful for and how they can differ from playing with real money.
Understanding how pokies work is only part of the picture. These guides help you keep gambling in proportion.
How to set budgets, deposit limits, loss limits and time limits, and the tools available to help you stick to them.
The warning signs that gambling is becoming a problem, for yourself or someone close to you, and where to get help.
For support services and self-exclusion options, visit our Responsible Gambling page. If gambling is causing you harm, call Gambling Help Online on 1800 858 858, available 24/7.
Once you understand the basics, you can see how these mechanics work in real games. Our Slot Game Reviews break down individual titles, and our Slot Game Providers section explains the styles and signature features of the studios behind them.
Start with What Are Pokies? and How Do Slot Machines Work?, then read the guides to RTP and volatility. These four cover the ideas behind almost every other topic.
No. Pokie results are random, and no knowledge or strategy can change the outcome of a spin. Our guides help you understand what you are playing, choose games that suit your budget and expectations, and keep your gambling under control.
The core ideas, such as random outcomes, RTP and volatility, apply to both. Features and rules can differ between land-based machines and online games, and our guides point out the main differences where they matter.
We review our guides regularly and update them when game mechanics, industry practice or regulations change. Our Editorial Policy explains how we keep content accurate.