It won’t surprise you to learn that we love slots. From their varying shapes and sizes, to the way they can turn newbies into big money winners with a single spin, slots really do stand out. We want you to love slots as much as we do, which is why we've compiled this comprehensive guide. Using it as a starting point should help you to pick your next online slot site with confidence. Then you’re ready to use our up-to-date ranking table below, where you can pick up an exclusive bonus on your way to playing at a site recommended by our slots-crazy review team. 

*T&C apply” – each offer may include additional conditions. The applicable casino’s T&C apply for each offer below and we encourage you to review them. Click “Get Bonus” for more information

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Understanding Online Slots and How to Find the Best Places to Play

Without polling every online casino player in the world, it's tough to know exactly how popular slot machines really are. However, if we take the average casino lobby and look through the list of games, it's pretty obvious that online slots are the top rated options out there. For example, if you follow our link to one of our best slot sites, Casumo, you'll see the lobby is filled with more than 200 titles.

Because the online casino industry is a supply and demand business, it's possible for us to say that slots are extremely popular simply because there are hundreds of them. In fact, when you look through the list of titles from top developers such as Microgaming, NetEnt and Betsoft, the sheer breadth and depth of their catalogues is the biggest indicator that slots are the most popular online casino games around.

The Main Slot Types

Variety is the spice of life in the casino slots world, and when you play for free or real money at any of our top UK gaming sites, there are three main options out there. Although there are variations on these general themes, you can broadly categorise all of the best slots in the following ways:

Classic 3-Reel Slots

Featuring traditional slot machine symbols such as fruit, 7s and bars, these spinners typically have three reels and a single win line. It's also common for these games to have lower betting limits and smaller jackpots.

Other names for classic slots include Fruit Machines and AWP Slots. Essentially, any game that has low stakes betting, three reels and a select number of paylines can be classed as a Classic, Fruit Machine or AWP slot.

Video 5-Reel Slots

The most popular casino slot machines online, video slots generally contain five reels and as many as 100 win lines. The main premise behind these games is entertainment. Through a combination of 3D images, animations, video clips and interactive bonuses, these slots are considered to be big on fun whether you play for fun or real money.

Progressive Jackpot Slots

Only available for real money play, jackpot slots are often considered the kings (or queens) of the online slots world. When you play one of these games, you'll be part of a network of players that are all contributing to a single prizepool. Because a small portion of each bet you make is going into a communal pot, the jackpots available can reach six and seven-figures with ease.

Mega Slots

When five reels just aren't enough, mega slots are the answer. With six reels of action and multiple paylines, these online spinners are capable of making even more winning combinations than their video slot counterparts. As you'd expect, mega slots will only release their jackpots when you match six top ranking symbols. However, for the added effort this requires, you'll win a lot more money. 

Choosing the Perfect Slots Casino

Choosing the best slots casino is always a matter of personal preference and, if we're honest, something of an art. However, that doesn't mean you can't take a scientific approach to things in a bid to narrow down your options. With dozens of high quality options out there, it's important to have a plan of attack before you sign on the dotted line.

With this in mind, we've compiled a list of things you need to assess before establishing which platforms are the best slot sites for you:

Slots Selection

As we've already said, there are hundreds of online casino slot machines out there, so any site worth its salt needs to have a large majority of them on offer. While we're not saying quantity is everything, you should expect to see more than 100 titles from a variety of software developers before you sign up.

Slot Bonuses

Slots are a great way to clear bonuses because you can place a large number of bets in a short space of time and, therefore, clear wagering requirements with relative ease. From this, you should expect to get at least a welcome bonus when you join. However, in an ideal world you want the best slot sites to offer no deposit bonuses, free spins and reload rewards as well.

Free Play and Mobile Slots

When you join one of our top rated slot sites, you'll notice that you can play for fun in a free game, and via your mobile. Modern slots gaming is all about spinning in a way that suits you, which is why you should demand practice games as well as mobile slots. That way you'll be able to play anytime and in any way you like.

Safety and Security

The final markers of quality you should be looking for are linked to safety and security. All of our partner slot sites are licensed by established gambling commissions. This means that every game, feature and bonus they offer will be regulated. Moreover, as part of any licensing deal, an online casino must prove its games are fair by having their random number generators (RNGs) certified by a third-party testing agency.

  • Huge slots selection
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How to Play Slots

Hopefully by now you know how to navigate your way around the slots world. However, before you can spin like a pro, you need to know how to play slots. Fortunately, one of the reasons slots are so appealing is because they are simple to play. In fact, once you master the basic terms below, all you really have to do is spin and wait for the money to roll in.

Slots betting explained

So, before you rush off in search of a fortune at one of our top slot sites, here's a quick guide to the slots lingo you need to know:


In simple terms, an online slot can have three or five (sometimes six) reels that sit in place and are made up of two components: symbols and paylines. Each of the games symbols (images) are printed on a single reel and each will spin independently of the other. When the reels stop spinning, matching symbols aligned across an active payline from left-to- right will unlock a prize. Depending on the slot game, there can be between one and 50 paylines spread across the reels.


Most modern online slot games have multiple paylines running from left-to-right across the screen. To bank a win, you need to match three or more symbols from left-to-right across an active payline.

What is a payline in slot games - Top 5 Casino Sites


Before you can spin, you need to place a bet. Depending on the game, you will have to set one, some or all of the following variables: coin size (the cash size of your bet), coins (the number of bets you're making per line), and lines (the number of lines in play). If more than one variable is present, the sum of the two values will determine the size of your overall bet.


All the best slots have in-game bonuses. These are typically unlocked when you roll in wilds (symbols that can substitute for any other) and scatters (bonus symbols). Depending on the slot, bonuses can come in the form of instant cash, multipliers (i.e. it multiplies any wins by a set amount) or free spins.


Online slots are often rated according to their volatility, which basically refers to how often they payout some prize money. The way a slot's volatility is judged is by its return to player (RTP). Always somewhere around 90%, the lower the RTP, the more volatile a game is (i.e. the less frequently it pays out money).

When it comes to assessing the value of a slot based on its volatility, games rated as "low" usually payout smaller prizes more often. In contrast, high volatility games won't give you as many wins, but when you do bank a prize it will be worth a significant amount of money.

Slots payline winning chances - Top 5 Casino Sites

How to spin a slots win…

Once you've learned some basic terms, the flow of a slot game online is as follows:

  1. Load up the game and set your bets using the available variables. Depending on the game, you may be able to adjust one, some or all of the following: coin size (the cash amount you're betting per line), bets per line/level (the number of coins you're staking per line) and the number of active paylines.
    **When it comes to paylines, it's important to note that some slots allow you to adjust the number of active paylines, while some don't. Additionally, a series of three or more symbols must be connected across any active paylines in a left-to-right fashion. Although this is different in some games, it's generally the case that wins are made from left-to-right.
  2. Every variable you adjust will affect the overall price per spin. For example, a coin size of £1 across 20 paylines will cost £20. Moreover, if you were to increase the number of bets per line to five, you'd be wagering £1 X 5 per line (£5), a figure which would then be multiplied by 20 win lines i.e. £100.
  3. After setting your bets, the spin button will start the game and the aim is to match three or more symbols to unlock a prize. Payout tables typically list multipliers as prizes such as 5X or 500X. This multiplier will be applied to the size of your line bet (not your overall bet) to determine the value of your prize. 
  4. In addition to rolling in fixed prize symbols, scatters and wilds help improve the number of ways you can win. Scatters are essentially bonus symbols that will unlock a series of free spins or a bonus round where you can win cash prizes or spins. In addition to free spins, three or more scatters will also activate a win multiplier (applied to anything you bank during your free spins). Finally, scatters also release instant cash prizes before the bonus round starts.
  5. Wild symbols are used as substitutes for all symbols except for scatters. As well as helping to create more wins, wilds are also used as the jackpot symbol. So, if you can roll in five wilds, it's often the case you'll pick up a slot's top prize. In terms of the wilds you'll find online, these are the most common:
    • Regular Wild
    • Expanding Wild (this can stretch over an entire reel)
    • Random Wild (can appear anywhere at any time)
    • Stacked Wild (this is when two or more wilds can be stacked in order to cover more parts of a reel)

Play for Free!

Because the top online slot sites want you to sample the latest and greatest spinners, you'll be able to enjoy the rush of the reels for free. Using "practice" or "demo" slots, you can experience everything the best titles have to offer without touching your bankroll.

Naturally, when you play free slots, you can't win real money. However, the flow of action is identical to what would happen if you were playing for real. In fact, one of the best reasons to play free slots is to hone your skills. Instead of jumping into a new game without understanding the rules or the best ways to bet, you should play it for free first and then make the switch to real money.

The only slots you won't be able to play for free are progressive jackpot spinners. Because these games are all about the communal prizepool and winning some serious prize money, there's no room for people not willing to spend in these games.

Slot Tournaments

In line with free play slots adding another dimension to the genre, slot tournaments also bring something different to the mix. Based on the simple premise "the more you spin, the more you could win", slot tournaments are great for those with a competitive side.

Although the top online slot sites will have slightly different rules, entry fees and prizes, tournaments usually play out in the following way:

  • You pay an entry fee and you're given virtual credits to play or you play for real money on the specially selected games.
  • You're given a set amount of time to accrue as many points as possible. Points are based on the amount of money you win. Penalties are sometimes imposed on players that lose all of their virtual credits.
  • The player/s with the most points at the end of the tournament will win a share of the prizepool with the winner receiving the most money.

Progressive Slots: Bet Small, Win Big

To conclude our look at online slots, we want to give you a few more details about progressive jackpot slots. As we've already said, these games are popular because they offer you the chance to win a huge prize from a small investment. Naturally, the way you win is determined by the game itself, but the usual road to riches features either five jackpot symbols or a jackpot mini game where you have to match mystery symbols in order to win the top prize.

Some of the biggest names in the progressive slots world include: Major Millions, Mega Moolah, and Playtech’s DC Comics games featuring Batman and Superman. All of these games can carry jackpots topping £1 million, with Mega Moolah currently holding the world record online slots payout at £13,209,300!

To join the action and spin some serious win, make sure you check out our selection of top online slot sites today.

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