Online Slots – Your Trusted Guide

Welcome to Casinopedia’s definitive guide to online slots; when we say everything, you need to know about online slot games, we mean it.

Use the links below to make sure you are kept updated on everything that is hot and happening at in the world of online slots, including expert advice and top tips to make sure you play smarter.

When you are finished head over to the casinos section of the site to check out the latest bonuses and ratings from the best online casinos.


Getting started

Slot machine games made the move to the online casino world in mid 90s and has grown massively, yet there are new players spinning the reels for the first time every day.

Despite the proliferation of online slots, a lot of newcomers are unfamiliar with the concepts, where to find them, exactly what’s going on with bonus rounds and how to deal with online casinos.

That’s where this guide comes in. If you’re new to online gambling and curious about slots, or just want to read some useful information about this growing arena, check out this back-to-basics information.

From five-reel slots to progressive jackpots, from welcome bonuses to the random number generator, we’ll examine the terms and tricks needed to understand online slots.

Slots basics

Starting simple, an online video slot (or just ‘slot’) is an electronic, internet-accessed version of the traditional slot machines seen in amusement arcades. A slot machine player places a wager, then three or more reels, covered with symbols, spin in the machine.

If the reels stop with a winning combination of symbols in view, the player wins some money from their wager.

Online slot machines recreate this process with software, but you still see reels spinning. Some have even moved on to other ways of displaying the symbols, but the principal of looking for a winning combination has stayed. Modern video slots typically have five reels instead of three, which allows for more combinations and special features.

They also tend to have more than one ‘win line’ or ‘payline’, which means that instead of just looking across the middle three spaces for a winning combination, you can get wins from diagonals, zigzags and more. This can certainly confuse new players who don’t know how the lines work, as it makes wins seem arbitrary until you check out the paytable for the game and see how the combinations play out. All the best slot games have some kind of information panel that explains more about features and wins, so this is the first thing to look for.

It’s also worth looking out for demo mode, which many casinos provide for their online casino games, depending on the slot developer. This allows you to play the game just for fun, rather than wagering real money, while you figure out how it works. This is also a good way to see what you think of the game in general, from the features to the animations.

Speaking of which, features are another big plus point of online slots. Advanced in the graphical capabilities of internet browsers allow modern online slots to feature video, music and constant animation, even 3D effects. These are used to turn a simple bonus game into an interactive video-game-like feature.

Jump to slots section:

Types of slot machines [icon name=”angle-right” class=”” unprefixed_class=””]
If I had dollar for every time someone said “a slot machine is just a slot machine”; luckily they are very wrong!

Understanding a paytable [icon name=”angle-right” class=”” unprefixed_class=””]
For experienced slot players, reading a paytable is second nature; we are here to try and make it as easy as possible for all players.

How to choose a slot [icon name=”angle-right” class=”” unprefixed_class=””]
There are so many online slot games at a whole host of online casinos, so we are here to try and help you choose the best one for you.

How to get the best bonus [icon name=”angle-right” class=”” unprefixed_class=””]
We all love a bonus, but some are better than others and why you should always read the small print first.

How to increase chances of winning [icon name=”angle-right” class=”” unprefixed_class=””]
We reveal the hacks that are making casinos furious because they are giving the edge back to players.

All about progressive jackpots [icon name=”angle-right” class=”” unprefixed_class=””]
When we talk about progressive jackpots, we are talking about life changing sums of money! Why wouldn’t you want to read on…

How to withdraw your winnings and what to expect [icon name=”angle-right” class=”” unprefixed_class=””]
Withdrawing your winnings is every players favourite thing to do, but there are some things that you need to know first.

How slots work [icon name=”angle-right” class=”” unprefixed_class=””]
Slot games have come a long way from traditional fruit machines, and some of the secrets behind the spinning reels.

The top slot games and where to find them [icon name=”angle-right” class=”” unprefixed_class=””]
The names that you should be looking for when it comes to picking your next slot and the casinos where you will find some of the most popular slot games around.

Glossary of online slot terms [icon name=”angle-right” class=”” unprefixed_class=””]
Online slot games may be simple to play, but do you know your RTP from your RNG and your base game from your demo play?

Types of slot machines

There are a few different types of slot machines online. The main distinction is between classic three-reel and newer five-reel games. Aside from the obvious difference in the number of reels, the former type is much simpler and reminiscent of a traditional mechanical slot. The latter slots tend to have all the features, music and multiple paylines. Occasionally, there will be slots with even more reels, as part of special features.

You should also watch out for variations on ‘ways to win’, which usually refers to how winning symbols are counted. Typically, a row of winning symbols is counted left to right, from the first reel. Some games, like NetEnt’s Starburst which can be found on casinos like bgo Casino, allow wins to count right to left, from the last reel.

This gives you more ways to make a winning spin.

Though most video slots still show reels, some developers have broken away from that image, since there’s no actual reel involved. Instead, the symbols just refresh randomly with each spin.

Avalanche or cascading slots do the same, with symbols seeming to fall into place from above- with the added twist that after a winning combination is made, the symbols disappear and more drop in, potentially causing more wins.

A prime example is another NetEnt game, Gonzo’s Quest- this can be found on many casinos, such as Power Spins Casino. The same mechanic, with tweaks, appears in slots by Quickspin, IGT, WMS and other developers, with terms like ‘Tumbling Reels’.

Understanding a paytable

New slot players always get a little fazed by the paytable. At first, the amounts you win seem very random- some symbols appear, there’s a flash or animation, then you win maybe a third of your bet. Then you spin again, seem to get the same result, yet this time you quadruple your bet! The quickest way to work these wins out is to check the slot’s paytable, which is usually revealed by a button near the reels.

The paytable will show symbols from the reels, with numbers by their sides. This may seem to be in code at first, but what this is actually showing is the value of each symbol, based on how many you land. For example, if a cherry has a 10, 20 and 30 beside it, the 10 is likely for getting 3 in a row, the 20 for 4 in a row and the 30 for 5 in a row.

Some confusion also arises from the fact that this number is not the amount you win- bear in mind that you can play various different stakes, so the paytable can’t always know your exact bet size. Instead, the number is how many ‘coins’ or how many times your bet that you’ll win. Paytables will also show which symbols are wild and explain any feature rounds.

Check out our top slot games and where to find them using the link below.

Top Slot Games

How to choose a slot

When it comes to picking a slot, a little trial and error is usually the best bet. Most slots behave quite similarly and the main differences are in the aesthetics and features of the individual games, so you’re free to choose things you enjoy. Demo mode is also very useful in this regard- try a few spins without spending any money, so you can save it for the game that speaks to you.

One thing you can do is narrow down the selection using categories. A good online casino like LeoVegas will offer category buttons to help you split the selection into slots, classic slots, newest games and so on. Some even let you choose a certain slot provider or studio. Watch out for which games have progressive jackpots, special features and different minimum and maximum bets. For example, if you’re trying to make your money last, a slot with a low minimum bet is ideal. This can be worked out by tweaking the paylines and stake size.

Last but not least, the best slot for you may be the one that’s also on the best site for you. A bit part of your gaming experience is determined by the quality of the site it’s on, with a large factor being the bonuses and promotions you can take advantage of.

How to get the best bonus

Casino welcome bonuses are a kind of universal promotion that almost all sites recreate in one form or another. This is how online casinos get new customers, so as a new player you have the pick of any number of bonuses. Many players even join several sites to get more bonuses.

Most welcome bonuses follow this pattern: your first deposit is matched by a certain percentage, up to a certain limit. For example, Casumo recently offered a 200% bonus on your first deposit, up to £50. This means that you could deposit £10 and get £20 is bonus money, a total of £30 to play with. The site also throws in free spins for new players!

However, don’t rush straight to the site offering the most extra money. All bonuses come with some kind of terms, usually a wagering requirement. This means that you need to spend the bonus at the site, and often a lot more besides, before you can withdraw any wins. The standard amount is 40 times, so if you get £10 in free cash, you need to bet £40 on the games before your winnings are released. So long as wins keep trickling in, this isn’t as hard to hit as it sounds.

The ideal way to find a good bonus quickly is to use listings, such as ours at Casinopedia, where the best casino bonuses have already been collected and compiled for you to choose from. Here’s a quick roundup of the best available anywhere online:

Online Casino Bonus Play
bgo Casino
£10 free + double your first deposit
200% bonus up to £100 + 50 free spins
LeoVegas Casino
£1,600 bonus + 120 free spins
Casumo Casino
£1,200 bonus + 200 free spins
Mr Green Casino
£100 bonus + 200 free spins
Gala Casino
£400 slots / £200 roulette bonus
Paddy Power Casino
£500 welcome bonus
32Red Casino
320% bonus up to £160
Betfair Casino
£400 bonus + 100 free spins

*Please ensure you read the bonus terms and conditions before you register and be aware that wagering requirements may vary.

How to increase chances of winning

While there is sadly no direct way to guarantee a win at an online casino, there are always tips worth bearing in mind. Here’s 3 of the best things to be aware of:

1. Stake
For many new players, the first question revolves around stake size.

When playing a smaller stake, your money goes down slower… but your wins are proportionately small. If you stake bigger, then you get less spins for your cash- but when you do win, you win bigger.

The best advice here is to find your own balance, to ensure that you get a good length of playtime out of your credit. Always stick to your budget! Some players will start with a small stake, then risk a higher one after getting a couple of wins.

You can also look into the volatility of slots. This refers to the risk of a game. A high volatility slot tends to land wins less often, but they’re bigger. Low volatility slots result in smaller wins, but more often. The latter is usually better for casual play. This information can often be found by searching slot names online.

3. RTP – Return To Player
Keep an eye out for the RPT or Return To Player of your slots, too. Most casinos will list this information, or it can be found online. This is what percentage of the bets going into the slot are paid back to players. A 95% game therefore only keeps 5% back as profit, the rest is paid in wins. The tricky part is that this refers to all players- you won’t always get that 95% back, because it applies to everyone as a whole. The higher an RTP, the more likely a slot is to give wins, even if they’re just small.

All about progressive jackpots

Progressive jackpots a big deal for both traditional and online casinos. Like a normal jackpot, these are hard to win, but they reward the player with large sums of money. Progressives have the extra twist of building up over time, so with each bet placed, they grow a little bit.

Always check a site’s slots for the current top jackpots, as they can reach into the millions before being won. Of course, the bigger the pot gets, the more competition you’ll get chasing it.

Some progressive jackpots are maintained specifically by the site you’re playing on. Others are the cumulative effort of a network. The Jackpot King network by Blueprint Games is the collective effort of all players on various sites. These massive pots can be found on sites like Sky Vegas Casino, on the Top Cat or Naked Gun games among others.

How to withdraw your winnings and what to expect

The withdrawal process is where all players want to end up, taking cash out of the casino after a big win! In many respects, this works just like a deposit. You will always find withdrawals in the same part of a site as deposits or your account information.

You can simply pick the amount you want to withdraw and follow a few steps. However, there’s sometimes a little more to the process. Make sure you’re aware of these 3 things:

Wagering Requirements
Firstly, if you had a welcome bonus or other promotional bonus, it may come as a shock that you cannot withdraw what you win. This will be because of a wagering requirement that you haven’t yet fulfilled. Always check the terms and conditions. If in doubt, simply contact the site support team, who will be able to check your details and explain the situation.

ID Verification (sometimes called ‘KYC’)
Secondly, there may be verifications to complete. Online casinos have to adhere to money laundering regulations as part of their licensing, which means they must ask some or all players (depending on individual policy) for identification, before a withdrawal is approved. This will often involve scanning and sending in photos of your payment card, driver’s license, a bill or passport.

While this can be a real pain, it is a legitimate process and it’s safe so long as you use a site with a good reputation, such as those listed here.

Minimum Withdrawal Amount
Lastly, note that the minimum withdrawal amount varies between sites. Some will let you take out £10, others make you have at least £30. This is worth checking before you spin yourself under the minimum and can no longer cash out.

How slots work

The slot games that you find on these online casinos may use similar layouts to traditional slot machines, but the systems within have changed a lot over the years. The obvious change from the days of real-world mechanical slots is the lack of actual reels and mechanisms. Online slots and indeed video slots seen in arcades work using an RNG instead.

The RNG or Random Number Generator is just what it sounds like, software which spits out numbers in a staggeringly high range. Numbers are pouring out of this program constantly, thousands in a second, so that when the slot game needs something to be random (i.e. when the reels spin), it checks the RNG and gets back an unpredictable number. This is then crunched down to a manageable size and it determines what the spin result will be.

This also means that the actual animation of spinning is a kind of illusion, as the result is decided behind the scenes, milliseconds after you click. The upside of this is that if you lose your connection after spinning, the result will still have been recorded and your winnings will be waiting for when you reconnect. RNGs are tested for fairness by independent bodies like iTech Labs, so look for casinos like Party Casino who sport logos of this or similar bodies.

The top slot games and where to find them

Mega MoolahLeoVegas Casino

Slot Title Recommended Casino Play Slot
Starburst bgo Casino
Gonzo’s Quest Mr Green Casino
Jurassic World LeoVegas Casino
Mega Fortune Powerspins Casino
Jackpot Giant bgo Casino
Rainbow Riches Casumo Casino
Age of Gods: Gods of storm bgo Casino
Major Millions LeoVegas Casino
Raging Rhino Casumo Casino
Thunderstruck 2 32Red Casino
Guns N’ Roses Mr Green Casino
Book of Ra Casumo Casino
Hall of Gods LeoVegas Casino
Arabian Nights Casumo Casino
Fairytale Legends: Red Riding Hood bgo Casino
Blood Suckers LeoVegas Casino
Lucky Leprechaun bgo Casino
Wish Upon A Jackpot Mr Green Casino
Aloha Powerspins Casino

View all slots

The hottest slots of the moment come from a handful of very long-established studios with excellent reputations. NetEnt is a very hot developer with 20 years of experience and a huge catalogue of high-quality games. They produce Starburst for a no-frills, colourful slot, or the Fairytale Legends series for very lovingly drawn characters like Hansel and Gretel. These can be found on Guts Casino and many others.

Playtech is another major player, well known for a series of DC comics slots. From Man of Steel to 60s Batman games, comic fans will love Playtech casinos like Or, for another range of games based on TV and movies, Microgaming produce Jurassic World and Game of Thrones slots. In fact, this prolific developer has made original games since online casinos first formed, with Thunderstruck II being a popular original title. They also produce the Mega Moolah series of progressive jackpots. These games can be found at William Hill casino.

Watch out for Blueprint’s Ted and Naked Gun slots for more movie action, or the very popular Yggdrasil studio for high quality, original animations like Vikings Go Berzerk, which is featured on Mr Green Casino.


Video Slot
Any digital slot machine game, with animations and software instead of mechanisms and physical reels.
The stacks of symbols on the slot display, usually three or five. These may not behave like actual rotating reels, but the term applies in most instances.
Spin The act of placing a bet, which spins the reels to get a random result, even if the slot in question does not use traditional reels.
Also known as a bet or wager, the stake is how much money the player risks when spinning the reels.
Also called win lines, these are the routes across the reels which count wins.Symbols
For each pay line, you are playing another bet, increasing the cost per spin.Scatter
Scatter symbols can appear anywhere on the reels- scattered around- to get a win, instead of relying on the win lines. They tend to be tied to bonus rounds in some way, too.

Wild symbols can substitute for other symbols, so they increase the odds of making a winning combination. The slot pay table will explain which symbols they count for.

Base Game
This refers to the slot’s default setting, which you see when you make a normal spin. This may behave differently to bonus rounds, free spin modes and other game modes.

Free Spins
Many slots allow you to win free spins, which are usually played out at a set stake value (often based on your last spin). Free spins are a great way to win more.

Welcome Bonus
A promotion which grants extra starting cash or free spins when you place your first deposit at an online casino. This bonus cash cannot be immediately withdrawn.

Playing for fun or for points, instead of wagering real money. This is ideal for checking a game out, but can’t win real money.

Progressive Jackpot
A jackpot which continuous rises until someone wins it, by taking a tiny portion of each bet placed. The more attention it attracts, the faster it builds up.

Return to Player (RTP)
This is how much, as a percentage, a slot machine pays back in winnings. This is typically in the 90% to 98% range and higher is better, but it is only an average.

Auto Spin
Some slots let you spin automatically, setting a number of spins or a certain budget, then letting the game play without you needing to click.

Random Number Generator (RNG)
The software at the heart of a casino that uses random numbers to create random effects for the slots, a kind of virtual dice roll.

Bonus Feature
Also known as a bonus round, a feature on a slot game can be anything from free spins to a whole animated sideshow, which interrupts play and offers big wins.

Wagering Requirement
This is a minimum spend which comes along with taking bonus money. The idea is to prevent players committing fraud by depositing their money and withdrawing bonus money.

Hot Streak
Also called a ‘lucky streak’, this refers to the event of getting several wins in a row, which is very lucrative. This can be misleading for players, as a streak can end at any time.

Many online casinos also offer mobile play, either by connecting to the casino through a mobile browser, or downloading apps just like any other mobile game.

This is a list of symbols and their values, to help players see what each spin can win. This may explain bonus rounds too.

Approved Casinos

Want to try an online casino? Approved Casinos

Choose an approved casino from our carefully selected list. VIEW CASINOS