Slots Explained: RTP, Volatility, Paylines and What “Megaways” Means

Slots, called pokies in Australia and slot machines in the US, are the most played casino game in many countries and among the least understood. This guide explains how they work, wherever you play.

How a slot decides each spin

Every spin on an online slot is decided by a random number generator (RNG). The result is fixed the instant you press the button, and the reels you see are just a display of that result. Nothing you do, such as when you press the button or how you bet, changes the outcome. Machines do not become “due” a win after a losing run.

RTP: the long-term average

Return to player (RTP) is the percentage of all money staked that a slot pays back over a very large number of spins. An RTP of 96% means a long-run house edge of 4%. Online slots commonly publish RTPs in the mid-90s, though they vary by game and sometimes by operator. The figure is an average across millions of spins, so it says nothing about a single session. You can usually find a slot’s RTP in its information or help screen.

Volatility: how the wins are spread

Volatility (or variance) describes how a slot pays out.

• Low volatility: smaller wins arrive more often, so your balance moves gently.
• High volatility: wins are rarer but can be larger, and long losing runs are normal.

Two slots can share the same 96% RTP and feel completely different because of volatility. A high-volatility game can empty a modest budget quickly.

Paylines and ways to win

A payline is a pattern across the reels where matching symbols pay. Older slots have a handful of lines. Modern slots may have 20, 50 or more, and some use “ways to win”, where matching symbols on adjacent reels pay regardless of position. More lines or ways can change how often you win something, but the effect on cost depends on the game. In some games each line is staked separately, so more lines raise the total stake. In others a fixed total stake is spread across the lines, and ways-to-win games need not charge separately for each way. The game’s rules show the actual total stake and what pays.

What “Megaways” means

Megaways is a mechanic licensed by developer Big Time Gaming. The number of symbols on each reel changes with every spin, creating a different number of ways to win each time. With six reels and up to seven symbols on each, the maximum is 117,649 ways. The mechanic does not change the odds in your favour: each Megaways slot still publishes its own RTP and volatility.

Bonus rounds, free spins and jackpots

• Free spins and bonus rounds are triggered by specific symbol combinations and are built into the game’s RTP.
• Buy features let you pay to enter a bonus round immediately. They cost more per play and can drain a budget fast.
• Progressive jackpots pool a share of every stake, so the top prize can grow very large but is won extremely rarely.

Rules that vary by country

• Great Britain: the UK Gambling Commission limits online slot stakes to £5 a spin for players aged 25 and over (from 9 April 2025) and £2 for ages 18 to 24 (from 21 May 2025), and has banned features such as autoplay and spin speed-ups. Rules change, so check the regulator’s current guidance.
• United States: online slots are legal only in the few states with regulated online casinos, generally for ages 21 and over. Physical slots are widespread in casinos and tribal venues.
• Ireland: online casino licensing has not opened yet under the new regulator.
• Canada: Ontario regulates online slots; other provinces differ. The age is 19 in most provinces.
• Australia: online pokies cannot legally be offered to people in Australia. Land-based pokies are state-regulated in clubs, pubs and casinos.

Slot myths

• “A slot is due a win” is false because spins are independent.
• “Playing at certain times pays better” is false because results come from the RNG.
• “Higher stakes win more often” is false; they only change the size of the win or loss.

How to play within limits

Set a budget before you start and decide in advance when you will stop. Our free spend tracker can warn you as you approach a limit, and its “how long will my money last” calculator shows how quickly typical stakes add up. For more on the maths, see how casino games work.

How to read a slot’s information screen

A slot’s help or info page usually shows these items.

• RTP: the published return to player percentage. Be aware that some operators offer the same game at different RTP settings, so check the figure for the site you are on.
• Volatility: often shown as low, medium or high.
• Maximum win: the top prize as a multiple of your stake. It is reached very rarely.
• Feature rules: how free spins, multipliers and bonus buys work, and what they cost.

Signs you are playing too fast

Slots are designed for quick play. If you notice that you are topping up after each loss, playing longer than planned or losing track of spending, take a break and check your total in a spend tracker. Most regulated sites offer reality checks and time-outs that you can switch on in your account settings.

The bottom line

Slots are decided by a random number generator, and each has a published RTP. The house edge behind it gives the operator a positive expected return across repeated play, although actual revenue varies. Volatility decides how bumpy the ride is. No pattern, timing or stake size improves your odds, so set a budget first, understand the game’s RTP and volatility, and treat slots purely as entertainment.

Sources

• Gambling Commission: Online slots stake limit and game design guidance (gamblingcommission.gov.uk)
• Interactive Gambling Act 2001 (legislation.gov.au)
• Alcohol and Gaming Commission of Ontario: iGaming (agco.ca)
• Big Time Gaming: Megaways mechanic overview (bigtimegaming.com)
• eCOGRA: RNG testing and game fairness (ecogra.org)

18+ only (21 in most US states, 19 in most Canadian provinces for casino and betting). Gambling can be addictive. Free, confidential help is available: Great Britain: England and Scotland 0808 8020 133, Wales 0808 2819 265 (free, 24 hours), and GAMSTOP (gamstop.co.uk); US: National Problem Gambling Helpline 1-800-MY-RESET (the older 1-800-522-4700 also works); Australia: Gambling Help Online 1800 858 858 and BetStop (betstop.gov.au); Ontario, Canada: ConnexOntario 1-866-531-2600; Ireland: speak to your GP or the HSE. Never gamble money you need for living costs.