Slots are the biggest game group at any online casino, and the idea is simple: choose a stake, spin the reels and win if a winning combination lands. There is more going on behind the screen than the animation suggests, though. This guide explains how slots work: the random number generator, reels and paylines, Megaways, bonus rounds, bonus buys and jackpots.
Once you know the mechanics, the numbers in a game's info screen, such as RTP and volatility, make a lot more sense.
Slot is casino shorthand for a slot machine. The word comes from the coin slot that the original machines took coins through. In online casinos slot, video slot and fruit machine all mean essentially the same thing: a game where you spin reels and wins come from the symbols that land on screen. Older mechanical machines are often called fruit machines.
In Finnish, the loanword slotti also has an everyday meaning as a time slot, for example a broadcast or booking slot. In a casino context that has nothing to do with it: when people talk about slot games, they mean slot machines.
Every online slot runs on a random number generator (RNG) that produces random numbers continuously. When you press spin, the outcome is set by the numbers drawn at that moment; the spinning reels are only a presentation of a result that is already decided. Every spin is independent. The game has no memory, it is never hot or cold, and a win is never due. Its long-run RTP is built into the symbol probabilities and payouts and does not change while you play.
The classic layout is five reels and three rows, but three or six reels and extra rows are common too. The main ways to win are:
Wild symbols substitute for others, and scatter symbols often trigger a bonus round wherever they land. In many games winning symbols disappear and new ones drop in, so one spin can produce several wins in a row.
In Megaways games the number of symbols on each reel changes every spin, typically from two to seven. The number of ways to win is the product of those counts, so it changes every spin too, up to 117,649 with six reels of seven symbols. Our catalogue has more than a hundred Megaways games, most of them from Pragmatic Play and Red Tiger.
A bonus round is a special phase, usually triggered by scatters. The most common is in-game free spins, often with multipliers or extra wilds. Others include pick-and-click games and hold-and-win respins, where cash symbols lock in place and each new one typically resets the respin counter. In high-volatility slots much of the RTP sits in the bonus round.
Many newer slots let you buy the bonus round outright at a fixed price, typically tens or hundreds of times the base stake, such as 100x. A bonus buy does not make the game cheaper: its RTP is usually close to the base game's but can differ, and the swings are much larger because one purchase equals many normal spins. Hundreds of slots in our catalogue offer it, more than 400 from Pragmatic Play alone.
A fixed jackpot is always the same multiple of the stake. A progressive jackpot grows as part of every bet feeds the pot, until someone wins it and it resets to its seed amount. A local jackpot builds from one game or one casino and stays smaller; a network jackpot is shared across many casinos and can grow very large, with a very small chance of winning on any spin. Because part of the RTP goes to the jackpot, the base game returns correspondingly less. Our catalogue has hundreds of jackpot games, with more than 200 each from Red Tiger, Playtech and EGT Digital.
Slot is casino shorthand for a slot machine, a game where you spin reels and wins come from the symbol combinations that land on screen. The word comes from the coin slot of the original machines.
A random number generator decides each spin's result at the moment you press spin. The reels only display it, and wins are paid from the game's paytable.
No. Every spin is independent and the game has no memory of past results.
A mechanic where the number of symbols on each reel changes every spin, so the number of ways to win changes too, up to 117,649 on six reels.
Buying the bonus round directly at a fixed price, typically tens or hundreds of times the stake. It adds variance but does not make the game cheaper.