Slot machines are among the most popular casino games, both online and in person, but they can feel confusing if you have never played before.
Bright lights, reels that spin in seconds, and unfamiliar words such as “RTP” and “paylines” may leave you wondering where to start.
This guide is here to break it down. We will explain how slots actually work, the differences between land-based machines and online games, such as those available at Pay By Mobile Slots, and some key features worth knowing. By the end, you will have a clear understanding of how to read a slot game and what makes each one unique.
What Are Slot Machines and How Do They Work?
A slot machine is a game where reels spin to display symbols. You place a stake, press the button, and watch the reels stop. If the symbols form a winning combination, the game pays out according to its paytable.
Online slot outcomes are created by a Random Number Generator (RNG). This is software tested by independent labs under UK Gambling Commission (UKGC) rules to make sure every spin is random. One important point is that each spin is separate from the last. This means that results cannot be predicted and a previous losing streak does not make a win “due”.
The game’s paytable shows the value of each symbol and how any special features work. Paylines are the set patterns across reels where wins can potentially form, while some newer formats use “ways to win”, counting matching symbols on adjacent reels.
Key Terms
When you first play, a few words may often appear:
- Paytable – the information screen showing how wins and features are triggered.
- RTP (Return to Player) – a percentage showing how much a game is designed to return over the long term. For example, an RTP of 95% means that, over millions of spins across all players, £95 could be returned for every £100 staked. This is theoretical and not a prediction for one session.
- Volatility – describes the frequency and amount of potential wins. A high-volatility slot might pay less often, but in larger amounts, while a low-volatility slot might produce more frequent smaller wins. This is only a guide, as the RNG decides every outcome.
- Scatter symbols – icons that can trigger features such as free spins when a certain number appear in a single spin.
- Wild symbols – special icons that can substitute for others to help form a possible win.
Understanding the Different Types of Slots
Not all slot machines are built the same. Here are some common types you may see online at casinos such as Pay By Mobile Slots, or on a casino floor:
- Classic slots – usually three reels with symbols such as fruit, bells, or BARs.
- Video slots – often five reels or more, with graphics, bonus rounds, and animations.
- Progressive jackpot slots – a portion of stakes feeds into a prize pool that keeps growing until it is won.
- Megaways slots – a format where the number of ways to win changes with each spin, sometimes reaching hundreds of thousands of possible combinations.
- Branded slots – themed around films, TV shows, or bands, using characters, sounds, and visuals from the brand.
Each slot game has its own paytable and rules, so it can be useful to check how any features can be triggered before you play.
How Do You Place a Bet on Slots?
In land-based casinos, machines take cash or printed tickets that show your balance. You then select your stake using the buttons on the machine.
Online, such as when playing at Pay By Mobile Slots, you adjust the stake with plus and minus buttons on screen. Some slot games have fixed paylines, so your chosen stake applies to all of them. Others let you choose coin values or the number of active lines.
In the UK, online slot spins must cost no more than £5 per spin if you are 25 or over, and £2 if you are aged 18–24. These limits apply regardless of the game. Each spin also takes at least 2.5 seconds, and autoplay is not available on UK-licensed sites.
Key Slot Features Explained
Understanding a few core features can make the experience clearer and help you choose games that might suit your preferences. These points appear in most slots, whether in a casino or online.
Paylines and Reels
Reels are the vertical columns that spin and stop to display symbols. Many classic slots use three reels, while video slots commonly use five or more.
Paylines are the invisible patterns across those reels where wins can potentially land. Some games have a single straight line, others offer dozens or hundreds of lines that zig-zag across the screen.
Certain formats replace traditional lines with “ways to win,” where a number of matching symbols on adjacent reels count from left to right, and sometimes both directions. Megaways is one example, where the number of potential combinations changes on every spin.
The paytable or info screen should show how the slot game handles lines or ways, along with which symbol sequences can create a return.
Symbols and Bonus Rounds
Symbols are the images that land on the reels, from classic fruits and BARs, to themed icons. Many games include special symbols.
Wilds can usually substitute for regular symbols, and in some titles they may come with multipliers or expand to fill a reel.
Scatters typically trigger a feature, such as free spins, if a certain number land anywhere in view, on the same spin.
Bonus symbols may start a separate game, for instance a prize-pick round or a wheel that can award fixed amounts or entry to a potential jackpot feature, depending on the game.
Bonus rounds can vary widely. Some may add modifiers like sticky wilds that remain in place for a few spins, others might include increasing multipliers or extra reels. The game’s info section should outline how each feature works.
Return to Player (RTP) and Volatility
The RTP is presented as a percentage that reflects the game’s long-term design. For example, an RTP of 96% suggests that, over a very large number of spins, £96 may be returned for every £100 staked across all players. Individual sessions can differ from that long-term model.
Volatility, sometimes called variance, describes how swings in results might feel. High-volatility titles have the potential to deliver less frequent, larger swings, while lower-volatility games tend to award smaller possible returns more often.
As noted earlier, outcomes are produced by an RNG, so the RTP and volatility act as guides rather than guarantees.
How Do Online Slots Compare to Land-Based Slots?
Online slots give you access to a much wider choice in one place, with themes ranging from simple fruit machines, to elaborate licensed titles. Features such as sound settings and game information are built in. Online games can also start from very small stakes, depending on the title.
Land-based slots are physical machines, usually offering fewer themes than an online library. Some players may prefer them for the tactile aspect of pressing a button or pulling a lever.
The main difference is variety and presentation, not the outcome. Both online and land-based machines use RNG technology, making results random.
What Should You Know About Slot Payouts?
Slot games are games of chance, which means there is never a guarantee of winning or receiving a payout. Every spin is random, and results cannot be predicted.
Each slot has a paytable, which explains how potential payouts work. Some wins are calculated as a multiple of the stake per line, while others use the total stake. Scatter symbols, for example, often pay based on the total stake rather than a single line.
Certain slot games may feature fixed top prizes, while others may contribute to a progressive jackpot. A progressive jackpot grows as players place bets, until it is eventually won. These jackpots always have their own special rules, which are clearly shown in the game’s information section.
Play Slots Online
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Log in or join Pay By Mobile Slots to explore a wide range of titles, from classic three-reelers, to video and jackpot games.
All games are provided in line with UKGC requirements to support fair play.
If you would like to see what is available, create an account to browse the full library and find games that fit your style.
Please only gamble if you are aged 18 or over. Set a budget you are comfortable with and consider using safer gambling tools to help you play responsibly.
*All values (Bet Levels, Maximum Wins etc.) mentioned in relation to these slot games are subject to change at any time. Game features mentioned may not be available in some jurisdictions.
**The information provided in this blog is intended for educational purposes and should not be construed as betting advice or a guarantee of success. Always gamble responsibly.