The world of slots is an immense one, and sometimes this can make them confusing for newcomers. With this in mind, we at Paddy Power Games thought it would be a good idea to cover some of the more basic and advanced concepts of slots alike, to keep our players up to date. If you want to know how slots work, slot rules, and almost anything else regarding how slots work, we designed this page for you.
Slot games are a form of gambling machine which derives its name from the slot into which money is traditionally inserted. These types of machines feature reels imprinted with various symbols that spin with each game. Upon gaining the correct combination of symbols, prizes and bonuses can be won.
With online and offline slots boasting a lot of moving parts, it’s easy to wonder - how does a slot machine work? Don’t worry though, they’re easier than you might think. To play a slot game, a player must insert a coin into a physical machine, or virtual currency on an online slot machine. Following this, the player then pulls a lever which starts the reels spinning. These reels can give no combination, resulting in nothing, or cause the game to pay out or enter a bonus state.
A row in a slot game refers to the horizontal placements onto which the symbols on the reels can fall. Commonly, there are three or five separate rows, though digital machines can offer many more possible paylines. It is the combinations of symbols across these paylines which give winnings should they appear across all or most rows.
Slot reels are the spinning barrels which make up the largest moving part of a slot game. The games' symbols are placed on the reels, in a manner that means the final resting locations of these random spins can give a wide variety of possible outcomes. The symbols that combine for the smallest wins tend to appear on the reels the most often.
RTP is the shortened form of "return to player". This is the statistical name to given to the proportion of money which a machine can be expected to return to the player in average play. Common RTP featured by most machines is around 89-95%, but you'll find a wealth of options inside our slots lobby.
Most popular types of slots
In many locations, the most popular types of slots are called straight slots. These are the simpler machines which contain basic pay tables. Another popular form is progressive slots, which have winning jackpots that gradually increase over time. Age of the Gods slots have also become really popular, and you can find a wide variety of AOTG slots there at Paddy Power!
Lets a player know about how much they can win, and on which paylines
The amount that a player has left to wager with
Shows the payouts for different combinations of symbols
The spinning part of a slot which contains the symbols
The amount which is bet on a single payline
Total number of lines which winning combinations can appear on
A button that maximises a player's bet instantly by increasing line bet and coin value to their highest values
Accepts the current settings and options, and spins the reels
The use of fruit machine symbols in slots came about in San Francisco back in the early 1900s. After banning the use of slots for gambling, the Industry Novelty Company came up with the idea to use the machines to sell gum instead. To accommodate this change, they changed the card symbols on the reels to fruit. A winning combination of a certain type of fruit would then pay out that type of gum. This was so popular, and fruit is so instantly recognisable, that they are still used as symbols to this day in many land-based and online slot games.
The number of symbols in a slot machine ultimately depends on the machine itself. Most standard machines tend to rely on around ten different symbols as the desirable maximum. Any more than this and the chances of gaining a winning combination can be significantly more unlikely, driving players away. In some case, however, as with enormous digital machines with a huge number of paylines and reels, the use of more symbols might be embraced to counter the increased winning odds.
Slot reel composition refers to the different combination of symbols which are included on a typical slot reel. These will depend highly on the machine, but generally include some combination of standard symbols, scatters, and wilds. Online slots, which have expanded potential than their hardware cousins due to software flexibility, also often include bonus symbols and multipliers.
These are the symbols which make up the bulk of the reel’s offerings. These usually appear as either fruit or playing cards, though themed slots can vary these appearances wildly.
On many machines, scatter symbols act as the gatekeeper to bonus games. For example, collecting three of these on an active payline can often give access to a separate minigame, or unlock the chance to try your hand at winning a jackpot.
Can substitute for any standard symbol the game offers (usually, scatters are an exception)
Similar to scatters, bonus symbols can give access to dedicated bonus games, or smaller bonuses within the main slot game.
Usually accessible from within bonus games, multipliers increase a winning prize by the multiple listed on the symbol.
These are symbols that, once landed on a spin, can persist on the reels for more spins. This is often the case with bonus features than involve wilds, such as sticky wilds. By doing this, it becomes possible for a player to gain winning combinations more easily, contributing to larger overall wins. In such a case, additional sticky symbols might maintain the sticky status, repeating each round until a spin yields no winning paylines, which will cause the sticky symbols on the reels to cease sticking.
Stacked slots symbols are fundamentally different from regular slot symbols in that they aren’t as randomised. Instead, stacked slot symbols can appear in large vertical groupings. When this occurs, it means that making winning combinations is much easier, as paylines can land much more effectively. Usually working with standard symbols, these can also apply over wild symbols in some fruit machines.
A special type of wild which is maintained over the reels for multiple spins, like sticky symbols. Instead of staying in one place, however, moving wilds can actively change their position on the reels after each spin to give the player more of a chance of landing a winning combination. These are usually given out by bonus features, lasting only a set amount of spins or winning combinations before vanishing from the reels.
Another form of non-stationary wilds which can remain on the reels for multiple spins. Wandering wilds operate by a specific pattern of movement which will eventually take them off the reels. A common example of this sees them move one reel to the left after each spin. In this case, they disappear after they reach the leftmost reels.
If a slot machine only features cards as symbols, the highest value symbols will start from ace, then go down to the king, queen, and so on. In other slot games, the highest value symbols can depend on the creator's whim. Fruit-based symbols, for example, have no objective measure of worth, so these will be scored arbitrarily. Slots which do not include cards or fruit will usually determine their symbol value based on their themes. For each online slot you can play here at Paddy Power Games, you can consult a paytable and short intro that shows you all the different symbols available, together with their value.
Like with the high-value symbols, the low-value symbols are often those based on cards. This will depend on the range of cards available within the slot game. Since most games will only go down from ace to around ten, ten will tend to be the lowest value symbol. In themed or fruit-based games, these values will have to be assigned based on suitability to a concept, or otherwise, be arbitrarily defined. Once again, you'll be interested in checking the specifics for each slot to figure this out.
How do slot paylines work?
Slot paylines have long existed as imagined horizontal lines which run across a slot machine's reels. Gaining a matching or otherwise winning combination of symbols along this line or lines would then generate a payout or bonus of some kind. Although paylines are often horizontal, the wealth of online slots means that some developers have created games that also involve diagonal or vertical paylines. Each game is different.
Single payline slots
These are slots which have a single payline which runs horizontally along the middlemost set of symbols. Such slots can be difficult to win, as winning conditions are strict, but this is commonly countered by offering large individual payouts and more limited ranges of symbols. Also keep in mind that single payline slots can also have a wealth of additional features. Their single payline does not always mean they are basic in their gameplay and mechanics.
Multi payline slots
Multi payline slots are a relatively modern feature popularised by online slots. These slots can offer dozens or even hundreds of different active paylines, meaning an enormous quantity of potential ways to win. These chances are usually managed by having more difficult to reach requirements per payline than single-payline slots, and lower individual payouts. Common examples of this are ten payline slots, though slot machine paylines can go much, much higher. For instance, our Kong the Eighth Wonder of the World online slot features 20 paylines, while Blue Wizard boasts 30 paylines.
Before we learn how to play slots at a land-based casino, we need to understand how much we wish to wager. Single coin machines are the simplest around, being able to be played with just one coin or token. After this, the machine is played as usual, and payouts will be made based on a single unchanging paytable. Multiple-coin machines, also called multipliers, can take multiples of a single bet, or a range of different coins of different amounts. This will multiply any wins by the added coin amount.
The BAR symbol on slots is a relic of the age of when some slots were replaced by fruit machines. The BAR symbol in these machines is thought to represent gum packaging, keeping with the fruit theme. In today’s machines, this symbol is usually offered as a high-value symbol, or occasionally a bonus symbol.
This is a question which comes from a method of cheating reported as being used in the now-distant past. On early metal machines, it could be occasionally possible to stop the reels or manipulate their movement using a powerful magnet. Today's machines are usually plastic or non-magnetic, and even those that are metal are immune to such old-fashioned schemes. We also suggest keeping magnets far away from your computer or mobile screen.
Another common misconception, and another case where the answer is a resounding no. The idea behind this is that the radio frequencies as generated by mobiles could mess with the internals of a slot machine's operation. In reality, machines are tested against this minute interference, so to create such an effect you would need to carry an industrial-sized radio tower into a casino.
Slots mostly differ from their physical casinos in that they offer a much wider range of gaming possibilities. This is because they rely mostly on software over hardware, which can let them do things which would either be expensive or downright impossible on physical machines. Moving symbols, complex bonus games, consistent additional randomisation, changing paylines, autoplay, and an enormous variety of other complex operations set online slots apart. That said, there are enough similarities that if you know how to play slots offline, you can probably figure it out online with no problems at all.
One of the most popular features of customisation available in online slots. Betting per line is what allows a player to change how much they want to wager on each payline. In some games with limited paylines available, this could only make a small difference to overall betting quantity. In games with dozens or hundreds of paylines available, changes to bets per payline will increase the total betting amount significantly. In other words, this depends on the total active paylines, bet levels, and coin values.
This refers to how many coins are being wagered on each active payline. Coins in online slots are fundamentally different than in their offline cousins in that the amount wagered can be much more flexible. This means that very few online slots could be considered single coin machines, with most instead standing as more diverse forms of multipliers.
Again, unlike with physical machines, in online slots, the player gets to determine how much a coin is worth. Combined with the total quantity of coins wagered per line, this lets players fine-tune both their total bet and the winnings which could be claimed of any active payline. Typically, coin value is set low, as most machines expect that the player will be placing bets concurrently over many different lines.
We get asked this alongside what a loose slot machine is, because they’re the same thing, in essence! Hot slots and loose slots are those which are considered to have a higher frequency of winning. Some online casinos keep track of this by making a note of which slots have been paying out more than average and then advertising this to the players via a banner or some other means on their main page. It should be noted that, unlike with physical casino slots, though, online slots are far less likely to break down to offer greater odds than what is usually available. As such, although many seek out these "hot slots" or "loose slots", the provably fair odds each slot offers means that, according to maths and statistics, these don't have more of a chance to grant you a prize when they're considered "hot" than they do normally. Instead, you may want to look into the concept of slots volatility. This shows how often a slot is expected to pay out. We'll explain the concept in detail a little further down.
The spin button in an online casino is just like an arm of an older physical machine, or a button on more modern devices. It simply takes the current bet and spins once. Autoplay, on the other hand, allows the player to set custom rules to keep the slots spinning for a certain amount of time. Common rules include running for a certain amount of spins, until a bonus game is won, or until a single win exceeds an entered amount.
This is a feature which partially or massively increases the speed of the spinning reels. Useful for those in a hurry, or those who simply don't like to wait, this can cut down the amount of time between spins considerably. Turbo mode is also often commonly used alongside autoplay so that multiple spins can be completed quickly and efficiently. Sometimes this feature will also cut out animations for additional speed, and remove sounds so that rapidly cycling noises don't become annoying.
These are the upper and lower limits on what can be bet in each spin. These limits are decided by the bet levels and coin values, and sometimes, the number of active paylines. Minimum bets will have the lowest overall coin worth, and coins bet per line, and the fewest active paylines. Maximum bets will be the exact opposite. It is also important to note that most modern online machines come with a maximum bet option, which will instantly set every option to the highest possible parameters.
This depends on the game itself. Most winning combinations will be simple symbol matches, but some online games can offer wins for other groupings, such as symbols which fall in a specific, unusual order. Paylines also come into play here, as many times these won’t be straight, meaning that winning combinations can be won on a zig-zag or other patterns. It's a good idea to check game paytables before you spin, to check to see if any unusual winning combinations can appear.
The RNG is the slot machine's random number generator. In slots, this is the code running in the background which ensures that the outcome of each spin is effectively unpredictable, giving no unstated bias to either the player or the machine. A more illustrative example of this are bonus features in games which have a chance of showing up with each spin, win or lose. In the background, the game might be rolling a die, and each time that die lands on a six, a bonus could occur.
If you’ve ever wondered how are slots random, then this is your answer. As for how you can trust casinos and slot machine developers, all reputable, licensed online casinos, just like our own, will prominently display on their site the third parties who frequently audit all games and ensure they are provably fair. This should give you complete peace of mind.
These terms relate to the predictability which is given to different slot games. High volatility slots are those which can go long periods with giving payouts, only to then hit the player with one large individual payout. Low volatility slots are those which are more consistent but have lower payouts given to the player per win.
In most ways, both variance and volatility in slot games are the same things. High volatility and variance mean that a game will pay out either nothing or larger amounts. Low volatility and variance mean that that the game will pay out often, just in smaller quantities. Of course, big wins are still available from most low variance/volatility slots, but the most common wins will be towards the smaller end of the spectrum.
Autoplay features will vary on a per-slot basis, but the underlying idea is the same. Players set their own autoplay rules, so they effectively let the game make the bets that a player would without actively having to keep tapping or clicking the controls. By setting end conditions, players can ensure that they’re there for the biggest wins, when bonus games are won, or after other strokes of good fortune. This also means that the slot won't continue to spin forever and players have full control of their bankroll still.
Online slots are programmed by dedicated slot machine manufactures that tend to exclusively focus on online casino software. This is accomplished by keeping a strict eye on gaming regulations, and building slots around these regulations which still offer something players find fun. Coding is the basis of this, but other contributions are also made by designers, artists, and musicians. Finally, these are also machine-tested to ensure true randomness and fairness. Luckily, players don’t need to keep track of this to know how to use a slot machine.
Ultimately, your choice in a slot game depends on your personal taste. High RTP slots can keep a player going for longer periods. if that is your thing, but others prefer to make different types of bets. Only by factoring in your wallet, your taste of theme, and what you want for a bonus, alongside RTP and variance, can you make the final choice.
If you want to get really good at slot games, you should also read our article about slot secrets, to find the latest slots tips and tricks.
At Paddy Power, we pride ourselves on our welcoming attitude. Because of this, we’ve come up with a great bonus for new players, so you can try out more of our excellent slots offering for less.
Of course, once you’re here, you’re going to need a reason to stay. While we know our selection of slot games is already one of the best around, we also run with constant and rotating promotions to keep our players engaged.
Cascading reel work by having winning combinations vanish from the screen. At this point, additional symbols will drop onto the reels. This can create a cascading effect, where win after win can clear out progressively more of the reels, if you are lucky.
A common question we see when people are figuring out how to play slots is "can you play online slots in demo version?". Here at Paddy Power, the answer is yes. We added this feature because we wanted players to be able to see whether or not a slot is right for them, and get you acclimated to a games bonus features before you play for real.
Expanding reels are features of bonuses which can expand the total amount of reels available to the player. This can ensure more combinations are possible, meaning the potential for bigger wins.
Expanding wilds are symbols which can grow to cover more of the reels than just one icon. While this can occur for many symbols, the most common example of this is found with wilds. These can grow from a single symbol to something like a 3x3 symbol, or become even bigger than that.
As the name suggests, this is a bonus feature which allows players to wager a prize in a double or nothing scenario. In other words, one win here will give you double your winnings, whereas a loss will remove this winning amount entirely. When deciding whether to take this offer, always consider how much you're risking
Nudges allow symbols to be moved a small distance to create superior winning combinations. This is commonly a system applied to wild and bonus symbols but be aware that you won't find it in every single online slot machine out there.
Fixed paylines are unable to be changed in any way by the player. One and 256-way slots often employ these systems.
Multiplier online slots usually refer to bonus systems which can multiply winnings by set amounts such as 2x, 5x, 10x, or 15x.
This means that winning combinations can be started from either side of the reels, not just the left. As combinations usually have to start from the first symbol, this can open winning possibilities immensely.
If you want to know how to tell when a slot is close to hitting the jackpot, then we have some bad news: there really is no way to tell. A slots random number generator means there is no predicting this still, and that’s a lot of the fun! After all, if players knew how to tell when a slot was close to hitting the jackpot, casinos wouldn’t last a day - and what would be the point of playing after all?
If you're new to the gambling world, you can learn more about slot machines strategies in our dedicated article.
The largest-ever payout for online slots was won on the Mega Moolah in 2015, measuring a massive £13.2 million by Jon Heywood. It may have been completely random but still, he really knew how to play a slot machine!
Can slots be rigged, and are slots honest? Rigging can happen, but we, like many casinos, take active steps to prevent this from happening. Ours are honest, and we take great care to ensure that fact. You will never find rigged slots at licensed online casinos that regularly undergo checks by the authorities.