Welcome to the school of slots UK! Are you bewildered by an alien world of online slots? Want to know your cascading grid slot from your nine-liner? or your scatters from your scatter pays? Or do you just want to find the safest sites where to play the best UK slots online? See the most trusted sites and bonuses or keep reading. If you are not from the UK then check out the online gambling site for other regions.
Here, we break down the basics, make sense of the jargon, and arm you with the knowledge you need to know to safely explore the different types and get the most from online slots. So, shake off that confused look, open your mind and get ready for the need-to-know, low-down in the School of Slots.
At our website you will find a list of the top sites in the United Kingdom. Listed are also all the bonuses and you can find lots of them!
There are so many different types of slots! Read our school of slots and find out more. We also list all the best casino slot sites and bonuses for UK players.
It stands for United Kingdom Gambling Commission. All sites we recommend are licensed by the UK Gambling Commission. Gamble responsibly. Age limit 18 or more.
All bonuses on our sites are for new customers only. All sites and bonuses are for UK players. If you are not from the UK please go to the International online casino pages or to the Finnish site kasinot.
Best UK slots sites online foreword
Before we get to the nitty-gritty, a serious note – Online slots are games of chance professionally designed to make a profit for an online casino. Remember, the mathematical odds of winning are always stacked against you and playing online slots should be nothing more than a fun pastime.
Play safe and learn how to shield yourself against potential addiction and gambling harm before taking a spin. Slots are a source of fun, nothing more, an entertaining thrill exchanged for disposable income.
How do Online Slots work?
Let’s start with a simple understanding of online slots and how they work. Online slots consist of spinning reels, each with sets of different symbols. Each symbol has a value, and the aim is to connect a matching set of symbols in an organised way for a win. The higher the value of matching symbols, the higher the win.
Upon pressing the spin button, a request is sent to the platform server for a result, and a random number generator (RNG) determines the outcome. The casino receives a notification to adjust your balance accordingly, and the reels come to rest, presenting the animation and result before the game is ready to spin again. Online slots are games of chance and unpredictable with random results.
The first slot machine, The Liberty Bell, had three reels, a three-row game window (3×3), and a single fixed line across the middle, the payline. Matching three symbols along the line would award a win. The payline is the original method used in the world of slots and the most common of slot pay systems.
Payline slots award wins when symbols match in succession along a route or line called the payline, traditionally from the leftmost reel to the right. Since the original single payline format, the natural progression was to add more lines to create more ways to win.
Pay systems grew along with game layouts to include more paylines, and games became known by their number of lines – five-liners, nine-liners, etc. Double Diamond from IGT is a classic online slot with a single fixed pay line. Its sequel, Triple Diamond, features nine paylines horizontally and diagonally. And the gaming giant’s legendary Cleopatra made the crossover from land-based machines into online casinos with 20 fixed paylines.
Today’s online slots have larger formats, more reels and more rows, creating amazing new layouts and opportunities for more paylines. NetEnt’s Archangels: Salvation has six reels and twelve rows (6×12), allowing 100 paylines.
Ways Slots, PayWays Slots, or Ways Pays Slots
Rising popularity and market competition pushed a search for new ways to captivate players, giving birth to ways pays, payways, or ways slots. Instead of using paylines, a slot with pay ways awards a win for matching symbols on adjacent reels in any row with no line to follow, traditionally from left to right.
Microgaming was instrumental in developing ways games, creating a range of 5×3 slots with 243 ways to pay, like the iconic Thunderstruck and Immortal Romance. Naturally, increasing the layout brings more ways to pay and today’s menagerie of reel formats means you can find 5×4 slots with 1,024 pay ways, six reel games with 729 or 4,096 ways to pay, and more. Megaways, the most famous of ways slots, offer up to 117,649 ways as standard, and games like Barcrest’s Beetlejuice Megaways reach up to 248,832 ways to win on a single spin.
Cluster Pays Slots
The next step in the evolution of pay systems came with cluster pays. A cluster is a group of matching symbols, horizontally or vertically adjacent anywhere on the reels or grid. An average of five matching symbols are the minimum required to form a cluster in most games, and the larger the group, the bigger the win.
Play’n GO’s Gemix made the genre highly popular in 2014, and many studios have since joined the ride. Reactoonz from Play’n GO and Jammin Jars by Push Gaming are some of the most popular cluster pays slots. Naturally, larger play areas increase the ways for cluster games to pay by allowing bigger sets to form.
Scatter Pays Slots, Pay Anywhere Slots
A scatter symbol is named so because of its function to pay or activate by landing anywhere on the reels. Widely used to trigger a bonus game for collecting three or more anywhere on a spin, the scatter symbol inspired the scatter pays, or pay anywhere slots. A scatter pays slot awards wins for matching a minimum number of symbols, usually five, in any position, anywhere on the reels.
Scatter pay systems are based solely on the number of symbols matched on a spin and pay more for a bigger collection of matching symbols. Pragmatic Play brought scatter pays slots out of the shadows and into the limelight in 2019 with Sweet Bonanza.
Dynamic Pay Systems
As developers strive to create the next big thing, new systems and ways to pay have emerged. Thunderkick’s Connecting Pay Ways system used on Gods of Rock and Odin’s Gamble award wins for touching symbols. Elk Studios Night Trax and SG Digital’s Spirit of the River experiment with diagonal, horizontal and vertical symbol connections.
An early twist on conventional pay methods came with Both Ways Pays or Pays Both Ways slots, which take a directional pays system, such as paylines or payways, and connects symbols in both directions, from left to right, and right to left. Adding a both-ways-pays system doubles the format potential and provides an entirely different gameplay feel. The Invisible Man by NetEnt is a classic example of a pays both ways slot. Today, AvatarUX has the PopWins series that pays both ways, like MonkeyPop and CherryPop.
Dynamic Game Mechanics & Features
Over time, reel formats and grids have reached their development peaks; after all, there are only so many reels and rows you can squeeze onto a screen. However, increasing the number of ways to pay has not been stifled or halted but rather grown and transformed through the development of dynamic mechanics.
Designed to amaze and impress, dynamic game mechanics complement spins with captivating win sequences, transform gameplay and increase the ways to pay in virtually unlimited numbers. Associated with innovation and outside the box thinking, no developer can claim to have influenced dynamic mechanics as much in recent times as Big Time Gaming with Megaways.
Big Time Gaming takes payways to the next level with the dynamic Megaways engine that randomly creates a number of rows for each reel on a spin. The average Megaways game format has six reels, each with 2 to 7 symbols generating from 64 to 117,649 ways to pay. Dragon Born launched the mechanic in 2016, and now licencing deals to partner studios see more than 300 Megaways titles in circulation in 2022.
The slot players’ flagship game of the series, Bonanza Megaways, includes a reactive win mechanic and a progressive win multiplier during free spins, which has formed the blueprint of scores of successful titles since, such as the NetEnt and Red Tiger Gaming collaboration Gonzo’s Quest Megaways, Pragmatic Play’s Great Rhino Megaways and Diamond Mine Megaways from Blueprint Gaming.
Cascading Symbols, Avalanche Reels, Tumbling Reels
Often used with grid slots and the cluster pays system, the cascading symbol mechanic removes winning symbol combinations from view, allowing gravity to take effect for existing symbols to fall into the space created. New symbols then cascade in from above to fill any remaining gaps, and the cycle continues if a new win is formed.
Known as a cascading spin sequence, tumbling or avalanching reels, and reactive wins on Megaways, the event can be lengthy and result in a trail of wins from the influx of new symbols with each cycle, leading to win after win. NetEnt’s Gonzo’s Quest slot introduced players to Avalanche Reels. Fast-forward to today, and the Gravity series by Elk Studios combines tumbling and sliding mechanics with circular symbols in games like Cygnus and Stars of Orion.
Expanding Reels and Grids, Added Rows and Reels
Many games increase the ways potential with layout-changing features that add an extra row, expand the reels, or grow the grid size. Starting with a default layout, winning combinations or game events alter the play area dynamically, creating more ways to pay.
ReelPlay’s Infinity Reels mechanic adds a new reel with each win, sliding the game window to accommodate. Another reel appears if a symbol matches to continue the combination, and the cycle continues until no symbols match. Playtech’s Split Reel feature on The Walking Dead 2 and Out of the Ice by Print Studios do similar.
Elk Studios Tahiti Gold and Ecuador Gold, start a spin with a 6×4 layout and add a new row of symbols with each win, expanding the format and up to 6×8 with 262,144 ways to pay. Relax Gaming’s Space Miners unveils rows with each win up to 1 million payways. Play’n GO has Payways, Yggdrasil Gaming has Splitz, and Foxium has Wonderways to increase the potential by expanding the format. Hacksaw Gaming’s Cubes and Cubes 2 work on an expanding grid built by sticky cluster wins.
Expanding Ways, Expanding Symbol Counts
By taking a 1×1 symbol and splitting it to contain more, expanding ways mechanics increase the number of matching symbols in the position, resulting in limitless ways to pay without the confines of the layout. Increasing the symbol count in a single position is an easy route to stacking up win ways for developers.
Nolimit City demonstrates the potential with its landmark title San Quentin xWays. The 5×3 video slot with 243 ways to win as standard reaches up to 13 billion ways to pay by splitting symbols with the xWays mechanic. Microgaming partners Northern Lights Gaming bring 60 million ways of potential on God of Fire Ultraways, and Elk Studios Nitro Reels on Nitropolis 1, 2 and 3 are fine examples of expanding ways features.
Wild Symbol Slot Features
NetEnt’s Jack and the Beanstalk slot uses wild symbols that trigger a respin and walk until exiting the reels, plus an assortment of wilds, including full reel wild symbols in the bonus. The developer’s Dead or Alive slot, and its sequel, Dead or Alive 2, have legendary status from sticky wild bonus games, the latter with multipliers.
Many online slots focus gameplay around the wild symbol that substitutes for all other symbols in winning combinations. There are slots with sticky wilds, expanding wilds, roaming wilds, nudging wilds, multiplying wilds, wilds that explode and others that trigger features and play a significant role in engaging players and fuelling game events.
Like wild symbols, multipliers come in all shapes and sizes and feature as core gameplay components for many slots. Hacksaw Gaming designs multiplying mechanics for highly volatile results, as seen on Chaos Crew and Wanted: Dead or a Wild. Hundreds of titles include a progressive win multiplier in the bonus game, increased by x1 increments with each win.
Multiplier wilds, symbol multipliers, reel multipliers, multipliers that increase as they nudge, and more provide excitement building entertainment when elevating standard wins into epic hits. Raptor DoubleMax by Yggdrasil Gaming has an unlimited doubling multiplier, which does not reset during free spins for jaw-dropping potential.
Deserved of a mention due to popularity, Book slots are a genre of games with a particular type of bonus game mechanic. During free spins, a specially selected symbol will expand to fill a reel upon landing, and using a scatter pays system, wins pay across all paylines. For example, three special expanding symbols would fill three reels and pay three of a kind across all paylines.
By far, the most famous slot from the genre is Book of Dead by Play’n GO. Other noteworthy titles throughout the history of online slots include Magic Mirror from Edict and the Book of Ra series of games by Greentube.
Progressive Jackpot Slots
Progressive Jackpot games put a large sum of money up for grabs by pooling a contribution from each bet. Since its earliest progressive jackpot title, Cash Splash, Microgaming has stolen headlines with an €18,915,872.81 win for a lucky player in 2018 on its Mega Moolah Jackpot Slot.
Red Tiger Gaming features Daily Jackpots across its games catalogue with hourly must-hit prize drops and daily progressive jackpots. Relax Gaming matched Red Tiger’s offering in 2022 with Dream Drop Jackpots and a €10,000,000 must-hit progressive jackpot.
Bonus Buy Slots
Since most players aim to trigger a bonus game and the bells and whistles it brings, many online slots come with a bonus buy feature, allowing players to skip the main game and buy a bonus round for a specified amount. Set by the game developer, the average cost of a free spin round or bonus game is roughly 80x your bet but varies dramatically.
Purchasing a super bonus on Tombstone R.I.P. by Nolimit City will cost 3,000 times your stake. Elk Studios xIter offers five unique spin scenarios and bonus rounds for different amounts. Relax Gaming expands on the gratifying concept with Bonus Reels, introduced on Money Cart 2, a variation of popular titles that feature scatter tease or bonus triggers on every spin at a standard cost.
Top 5 Tips for Playing Online Slots Sites UK
Online slots come in all shapes and sizes, but whatever genre or game type you lean towards, the aim is to match symbols in a particular way for a win. All that remains is eye-candy and appealing animation designed to captivate, amaze, and entertain.
Although the outcome of every spin is a random event, there are a few variables that can undeniably influence your playtime and experience. Consider your game choice, allocated funds, stake size, and ringfencing your time and spending as detailed in Top 5 Tips for Online Slots UK.
1. Play Safe
The fundamentals of safer gambling are simple – budget your time and spend. Before playing slots sites online, learn about safer gambling initiatives and the free-to-use tools available at good online casinos. Visit the our Safer Gambling page for hints and tips to get you ready to play online. (Link)
Play only with your disposable income and stick to your budget religiously. Breaking this golden rule of safer gambling can lead to consequences. Play a suitable stake in proportion to your deposit to increase your time on the reels, and don’t get carried away. Cashing out your deposited amount and playing with winnings or withdrawing a big win are sensible suggestions, but always remember that the design of games of chance is to attract and make money.
3. Know Your Game
A kaleidoscope of online slots can affect your balance in various ways, and your game choice will affect your experience. Online slot RTP and Volatility ratings can be found in the game information upon loading, giving an idea of the slot’s design and, loosely speaking, what to expect compared to others.
The Return To Player (RTP) rating is the tested return of the slot over millions, billions, and sometimes trillions of spins shown as a percentage. The higher the RTP percentage, the more the game is designed to pay back. Choose to play higher RTP games to increase your chances of winning. The smart slot player knows how much RTP can affect your playtime and balance.
Be aware that the same game may come in different RTP versions at other slot sites. The Book of Dead slot by Play’n GO comes in five different RTP versions for online casinos of 96.21%, 94.25%, 91.25%, 87.25% and 84.18%.
Volatility is your next consideration and a guide to the behaviour of a slot. Ranging from low to extreme, a game with low volatility may deliver frequent wins within a steady range, like NetEnt’s classic Starburst. A game with extreme volatility, such as Nolimit City’s Misery Mining xBomb, can have many non-winning spins, an erratic win range, and deliver a staggering hit once in a blue moon.
It is worth noting that the game developer accredits the volatility rating and not to a universal standard, so one studio’s high volatility game may feel very different from another’s. Your choice of volatility, like RTP, can dramatically affect your experience.
4. Set Your Expectations
So, you’ve set your safer gambling limits and picked your game. Now it’s time to set your expectations with some hard slotting facts. Remember that online slots are random and will behave as such, and just because a game played well on your last visit, do not expect it to behave the same way.
Due to the fraction of spins in the average playing session compared to a game’s testing, do not expect the slot to meet its RTP. In the same breath, choosing to play an extremely volatile game should not come with the expectation of a staggering hit, nor should a low volatility game be expected to pay back more often.
In short, the best expectation when playing online slots is to have none, which leads us nicely to our final tip.
5. Have Fun
Paying attention to your mood and being sure you are having fun is critical. Often, feelings of frustration, mood swings, obsessing over your next deposit or withdrawal from social situations are warning signs something is amiss. If you are not enjoying a spin of the reels, you might need to stop playing and take a break.
Best UK slots, bonuses and online sites
All the bonuses are for new UK customers only.