In the world of online casinos, slot machines are amongst the most popular things for people to play. They’re so popular, in fact, that even gambling sites that specialise in other products such as bingo, poker or sports betting will offer up a wide range of slot games to their players.
There are literally thousands of slots that players can choose from these days, with quirky features such as sticky wilds, tumbling reels and even ‘must win’ jackpots. Plus thanks to a series of lucrative licensing deals, you can find games themed around your favourite film and TV shows, and even rock bands.
In this section we’ll highlight some of our favourite places to play, including both slot sites that have the widest choice as well as those that offer up something a little unique.
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How Do Slots Work?
Whilst it might seem as though players of online slot machines have a modicum of control, the reality is that the outcome of games is entirely down to a Random Number Generator, which is essentially a computer program that decides on the outcome entirely at random. Such random sequences are created every millisecond, meaning that what happens in your game can be as much about when you choose to press the play button as anything else.
RNGs are regulated and spot-checked, ensuring that they’re as fair as they can possibly be. None of the spins of a slot machine have any impact on what has happened before nor on what happens next, so there is very little, if anything, that you can do to influence the outcome of a game that you’re playing. They also don’t have any sort of memory, so just because it has recently paid out a jackpot doesn’t mean that a jackpot is unlikely to be triggered again soon.
The best way to think of it is like with the flipping of a coin. Each time a coin is flipped, the previous result has no influence on the outcome of the next one. Just because it’s landed on heads 100 times in succession doesn’t mean that it’s more likely that it will be tails next time around. Before the coin is flipped, there’s an equal chance of it being heads or tails and so it is with the outcome of slot spins that use a Random Number Generator.
The only thing that does have a slight degree of influence on online slots is the volatility of the game that you’re playing. Those with high volatility will produce wins on a regular basis, but they’re much more likely to be small wins. Games that boast a low volatility will pay out less often but when they do the prize is likely to be bigger. Sadly, there’s no way of knowing which sort of volatility a machine boasts and you can only learn through the experience of playing.
Random v Compensated
One factor that’s worth thinking about when it comes to slot machines is whether they are entirely random in nature or boast a degree of compensation. In the world of online slots, it’s far more common for the games on offer to be entirely random, which compares with the sort of slot machine that you’d experience in a pub that is more likely to be compensated. The best way of thinking about a compensated slot is to think that the games have a memory.
With compensated slots, the game has a memory of how often it has paid out and therefore will be aware of whether or not it needs to give a big payout in order to meet its Return to Player percentages. We’ll explain what Return to Player means in a moment, but for now it’s worth realising that slot machines and online games have a given amount of money that they can pay out over a certain amount of time.
This is an extremely simplistic way of thinking about it but it is helpful to explain how compensated machines work. Imagine that a machine knows that it has to pay out once in every 20 spins. It has been spun 15 times without any of them being wins, so the machine knows that it has to payout within the next five spins. This is why you’ll often see people hovering around slot machines in the pub, waiting to see if the person using it wins and jumping on it if not.
Compensated machines are fixed in such a way that they will payout over a certain number of spins, with the amount of spins that have happened increasing the chances of it paying out on the next few. Random games, on the other hand, have no member of what’s gone before and will pay out in an entirely random fashion. You will be unable to predict when a game using an RNG is likely to offer a payout, so be wary of anyone that tells you otherwise.
What Is RTP & Why Does It Matter?
Every slot machine and game has to advertise its Return to Player percentage somewhere. Often referred to by its acronym of RTP, this is exactly what the title suggests it is: a percentage of money that is paid out over a period of time. The problem for bettors is that the period of time in question will be undefined and will take in countless different players. In other words, if a machine’s RTP is 97% then it will payout 97% of what’s paid in by all players.
An RTP of 97% would mean that the game would take 97 pence from every £1 spent on it, but it does those over a massive number of players. As a result, you might sit and play a game and spend £100 but only receive £85 back in winnings rather than the £97 you might have been expecting. That will be because another player at a different time will play the same game and be paid out £109, meaning that it’s hitting its 97% RTP but over two players.
The main confusion that people have when it comes to slots and their Return to Player percentage is that they look at a small sample and think it means something. In reality, you could play for a whole day on a machine with an RTP of 97% and lose more money than playing the same amount of time on a machine with a 70% RTP because of the small nature of the sample size. The main thing is that you’ll lose over the course of time.
Whilst the RTP is impossible to work out from a short amount of playing time, it is still worth thinking about it when you’re deciding which slots to play. You’re more likely to lose less if you spend a long time playing on slots with a large RTP than a small one, especially if you’re playing for a long period of time. Of course, the reality is that you’ll always lose money, inclining any winnings, if you play for long enough, so quit whilst you’re ahead.
Here’s a look at some slots with high RTP percentages and those with low percentages to give you a sense of what’s on offer in the market:
High RTP
| Slot | Software | RTP % |
|---|---|---|
| Ugga Bugga | Playtech | 99.07 |
| Mega Joker | NetEnt | 99 |
| Ooh Aah Dracula | Barcrest | 99 |
| Jackpot 6000 | NetEnt | 98.86 |
| 1429 Uncharted Seas | Thunderkick | 98.6 |
| The Catfather | Pragmatic Play | 98.10 |
| Rainbow Riches Pick n Mix | Barcrest | 98 |
| Jokerizer | Yggdrasil | 98 |
| Blood Suckers | NetEnt | 98 |
| Starmania | NextGen | 97.87 |
Low RTP
| Slot | Software | RTP % |
|---|---|---|
| Ghosts of Christmas | Playtech | 92.33 |
| Genie Jackpots | Blueprint | 92.09 |
| Funky Fruits Farm | Playtech | 92.07 |
| Black Widow | IGT | 91.99 |
| Satsumo’s Revenge | Playtech | 91.60 |
| Gladiator Jackpot | Playtech | 91.46 |
| Gladiator Jackpot | Playtech | 91.46 |
| Football Carnival | Playtech | 91.32 |
| Major Millions | Microgaming | 89.37 |
| Mega Moolah | Microgaming | 88.12 |
The list is far from exhaustive and there are actually some games out there that have even worse RTP percentages than those in the above table, but it does give you a sense of the difference in what you can expect to come across in the online slots world.
Slot Jackpots
One of the main things that entices players to get involved in playing on slot machines is the impressive jackpots that they offer. Thanks to progressive jackpots, the amount of money that you can win if things go right for you when playing the game can reach eye-watering levels, which is what makes them such popular things to play. Progressive jackpots work by taking a percentage of every amount spent on the game and adding it to the pot.
Obviously the more people play, the higher the jackpot goes, which makes such games different from standard jackpot offerings in which the jackpot is pre-determined and remains the same throughout. Even after the jackpot is won on normal games it remains the same for the next winner, whereas progressive jackpots will return to the minimum possible win and begin growing again, getting ready for the next winner to hit the big time.
How the jackpot is won will vary from game to game, though pretty much all of them involve some level of needing to hit certain symbols, whether you’re able to win the jackpot will often depend on how much money that you play with. It’s not uncommon for slots to require you to play with the maximum amount of money in order to be eligible to win the jackpot, whilst those playing with lower amounts will only be able to win a reduced amount.
It makes perfect sense, of course, with slot makers keen to encourage punters to pay a large amount of money regularly. At the same time, it could be considered unfair for someone paying 20p per spin to be able to win the same amount of money as someone paying £10 per spin, say. There’s a degree to which it’s only fair that those paying the largest amount are the ones that can hit the big time, though not all games operate in exactly that way.
Goodbye Flash
In November of 2020, Adobe confirmed that it would no longer be supporting Flash content from the end of that year. It was big news in the casino world, given that a large number of casino games and slots used Flash as the basis of the gameplay. As soon as rumours about that decision began to circulate, casino games makers began to convert their games over to use HTML5, which has been the case on iPhones for years.
Steve Jobs decided early on that he wouldn’t allow iPhones to use Flash because of the amount of power consumption that they used. This decision was justified in 2015 when numerous different security issues with Flash came to light. Since then, the casino industry has largely began to shift over to using the likes of WebGL and WebAssembly, as well as HTML5 instead of Flash, though numerous Flash-based games did still exist.
Most games created after 2017 will have been made with an alternative technology, but there are still a number of games that will have used Flash. As a result, fans of older games will have been sad to bid them goodbye as it became clear that it was going to be too costly to convert them to other software types. Flash, it seems, is now a thing of the past and therefore the only games that you’ll be able to play in the future will use a different software.