How Online Pokies Work — The Technical Guide
Online pokies may look simple — press spin, watch the reels — but the technology behind them is sophisticated. This guide explains the Random Number Generator (RNG) system, how RTP is calculated, how paylines and bonus features work, and what actually happens during every spin.
The Random Number Generator (RNG)
Every online pokie uses a Random Number Generator, a mathematical algorithm that produces a sequence of numbers that cannot be predicted. The RNG generates thousands of numbers per second, even when nobody is playing. When you press “Spin,” the RNG’s current number determines the outcome.
Key facts about RNG:
- The outcome is determined the instant you press Spin — the reel animation is just for show
- Each spin is completely independent. Previous results have zero influence on future results
- Legitimate RNGs are tested and certified by independent labs (eCOGRA, iTech Labs, GLI)
- The casino cannot manually adjust individual spin outcomes
- RNGs are seeded with unpredictable sources (system clock, mouse movements) to ensure randomness
How RTP Is Calculated
Return to Player is calculated across billions of simulated spins during game development. The game’s math model defines the probability of every possible outcome, and the sum of all payouts divided by all wagers gives the RTP percentage.
For example, a pokie with 96% RTP has been mathematically designed so that across its entire lifetime of play, it will return 96 cents for every dollar wagered. Individual sessions can deviate wildly from this average due to variance.
Important: Some providers offer casinos a choice of RTP settings. A casino might run Sweet Bonanza at 96.49% (default) or 95.45% or 94.09%. The setting is chosen by the casino, not the player. Always check the in-game info screen to see which RTP is active.
Paylines, Ways to Win, and Megaways
- Fixed paylines: Traditional system where wins occur along specific predetermined lines (e.g., 20 paylines). You must bet on all lines for full coverage.
- Ways to Win: Replaces paylines with a system where matching symbols on adjacent reels from left to right creates a win, regardless of exact position. Common formats: 243 ways, 1,024 ways.
- Megaways: Licensed mechanic from Big Time Gaming where each reel shows a variable number of symbols (2–7), creating up to 117,649 ways to win per spin. Used in titles like Big Bass Bonanza Megaways and Gates of Olympus.
- Cluster Pays: Wins are formed by clusters of matching symbols touching each other (horizontally/vertically), not by paylines. Used in Reactoonz and similar grid games.
Bonus Features Explained
- Free Spins: Triggered by landing scatter symbols (usually 3+). Free spins play automatically at your current bet size without deducting from your balance. Often include multipliers or enhanced features.
- Multipliers: Multiply your win by a factor (2x, 3x, 10x, etc.). Can be applied to individual wins, entire free spin rounds, or triggered randomly.
- Cascading/Tumbling Reels: Winning symbols are removed and new symbols fall into place, potentially creating additional wins from a single spin. Used in Sweet Bonanza, Gates of Olympus.
- Bonus Buy: Some pokies let you pay a premium (usually 80–100x your bet) to instantly trigger the bonus round, skipping the base game grind. Check your casino’s T&Cs as some restrict bonus buys during wagering.
- Wilds: Special symbols that substitute for other symbols to complete winning combinations. Some wilds expand, stick, or carry multipliers.
FAQ
Licensed casinos using games from legitimate providers cannot rig individual outcomes. The games run on the provider’s servers, not the casino’s. However, the casino can select a lower RTP setting if the provider offers multiple options. Always check the in-game RTP.
No. Each spin is independent due to the RNG. What feels like a “hot streak” or “cold streak” is normal variance within the game’s mathematical model. The pokie has no memory of previous spins.
The spin result is determined server-side the instant you press Spin. If you disconnect, the result is stored on the server. When you reconnect, the game will show the outcome and credit any wins to your account.