How Do Online Slots Work?

Almost everyone has seen slot games somewhere, either online, on TV, or even down the pub. But have you ever wondered how they work? Many people will tell you that they’ve figured out a fool-proof way to beat this or that slot, or that it’s all a fix and casinos control all the slots from a central hub, only giving winnings to the players they like.

Push aside all the conspiracy theories and speculation, because the team here at OhMyBingo have made it their mission to create a clear, simple, and honest guide to how slots games work.

In one form or another, slot games have existed for more than a century, and as gambling technology has advanced, so has the legislation used to govern it. No one wants to read huge legal documents, so we’ve broken down the important bits for you!

Take a look at some of the most-asked questions regarding how slots work, and you’ll also be able to see OhMyBingo’s carefully researched answers!

Are online slot games fixed?

Despite what that bloke down the pub says- no, online slot games are not fixed, and neither are the ones in UK land-based casinos. Slot games for UK players are carefully regulated by the government through the Gambling Commission, and slot fairness is something they take extremely seriously.

It’s worth noting that this guaranteed fairness only applies to casinos and providers who are UK licenced with the Gambling Commission! If you’re playing online, make sure you check this by looking at the bottom of the site page for the Gambling Commission logo or licence number.

If you play with a casino that isn’t licenced, not only have you got no guarantee that the slots aren’t rigged, if you have a complaint, the Gambling Commission won’t be able to do a thing to help you!

Gambling Commission logo and license.

How do the Gambling Commission guarantee fairness?

To operate in the UK, casinos and gambling providers must be regulated by the Gambling Commission, and that includes meeting their criteria and quality assessments. The Gambling Commission checks that all slot games are being run using something called a Random Number Generator, also called an RNG.

This is a computer algorithm which spits out random number sequences, and these translate to the places the online slot reels stop at. All UK online slots are run on RNGs, because this ensures that the result of each spin is completely and utterly random.

Why are so many people convinced that slots are predictable?

Despite the guaranteed use of RNGs in online slots, many people are absolutely convinced that they see regular repetitions or patterns occurring on slot games. This is a common psychological phenomenon, which is that human beings like to see patterns.

Patterns are good for survival- they help us predict threats that might appear, and avoid future risks based on things we have already seen. However, the brain does tend to overreach sometimes, and sees patterns where there just aren’t any. Human brains struggle with the concept of complete mathematical randomness, and when people are faced with it, they tend to “rationalise” the random sequences into a pattern.

Will my lucky pants help me score a win?

Superstition is deeply rooted in gambling, and has been since it began hundreds of years ago.

Whether it’s a bingo player’s lucky seat in the bingo hall, a lucky charm that a player carries with them, or checking for your lucky/unlucky numbers on a bingo card, most players will have some sort of ritual that they consider lucky. People repeat behaviours that happened when they had a win last time, in the hope that the same actions will result in a win this time.

Rationally speaking, bingo and slot games are pure chance, controlled (in slot games’ case) by mathematical algorithms that cannot be altered. However, many players swear by their lucky charms, and will simply refuse to gamble without them. And frankly, if you like wearing your lucky socks or sitting in your lucky seat to play, why not?

Four leaf clover

If a game just paid out, will it be ages before it hits again?

The simple answer is, not necessarily. The Random Number Generators which control how a reel lands have no memory, so they can’t “remember” or record if it’s been one spin or a thousand spins since the slot last paid out.

Each spin is entirely independent of every spin before it; if you just won a huge jackpot, you have exactly the same chance of winning again on the next spin.

What is independent probability and how does it affect slots?

In probability, there are dependent events, and independent events. An example of a dependent event is pulling cards from a pack without reshuffling it each time.

Example — Say you have a pack of cards and are trying to draw the Ace of Spades. You have 52 cards, and one of them is the Ace of Spades, so your chance of drawing it is 1/52. You draw a card randomly, and it isn’t the Ace of Spades. You put that card to one side, out of the pack. You now have 51 cards, and one of them is the Ace of Spades. The chance of drawing it is now 1/51. The more cards you draw and remove, the less there are left in the pack, so the higher your chance of pulling the Ace of Spades.

This is called a dependent event because the chance of your desired result happening (drawing the Ace of Spades) is directly affected by what happened before.

Independent events are not affected by what has happened before.

Example — You flip a coin, and it lands on heads. There was a 50/50 chance of it landing on heads. You flip the same coin again. There is still a 50/50 chance of it landing on heads. It doesn’t matter what it landed on last time, the chance of it landing on heads is exactly the same each time.

Spins on an online slot are independent events. Each spin is seen as a completely new event, as the RNG cannot “remember” what happened before. You have exactly the same chance of winning each and every time you spin.

That means that theoretically, you could win big, then win big again the very next spin. The slot game cannot “remember” that you just won and stop you winning again; the programme just doesn’t have the ability.

Do I have the same chance of winning on every slot game?

No, you don’t. Although you have the same chance of winning each time you spin on a single game, the chance of winning does vary from slot to slot. Good news though- you can see these numbers for yourself!

Each slot game you see online has a Return to Player, or RTP, value. This is the average amount that is paid out per pound wagered. It’s shown as a percentage, and is usually between 92% and 98%.

Example — A slot has an RTP of 97%. This means that theoretically, on average, for every £100 bet on the slot, the house will keep £3.

It’s very important to remember that RTP is a theoretical value based on all players betting on the slot across its whole lifetime. A slot with a 97% RTP isn’t a guarantee that if you bet £100, you’ll get £97 back. Don’t forget, the RTP includes players who have never won, and players who have won huge, so it’s an average spread across all players.

Do slot games have a quota or target to meet?

Slots don’t work like that, because the Random Number Generator controlling it can’t “remember” what has already happened; it just spits out number sequences. Slot games won’t tighten or loosen up towards the end of the month to meet a target; your chances are the same regardless of what day you play.

It’s also important to note that although an RTP gives you an idea of what kind of return you can expect from a game, slot machines don’t “try” to meet this number; it just naturally balances over time. A big win doesn’t mean the game will stop paying out to try to get back to its normal RTP, because it has no memory and can’t remember whether there was a big pay-out or not.

It’s like the coin-flipping example. If you flip a coin enough times, you’ll probably get a roughly-equal number of heads and tails. That doesn’t mean that if you get three heads in a row, the coin will “try” to get a tails, it just balances out over time. Slots work the same way.

Coin flipping

What else affects how a slot pays out?

One of the big factors in how a slot pays out is called volatility. This is whether a slot pays out “little and often”, or rarely but a bigger amount. A slot with high volatility might not pay out for days or weeks, but then when it hits, the amount won is huge. A slot with low volatility is likely to pay out much more often, but the wins will be smaller.

Should I play a slot with high or low volatility?

That really depends on how you like to play. Do you get frustrated if you go ages without a win? Or are you willing to wait it out in the hopes of hitting big? Neither high nor low volatility is “better”; it all comes down to how you like to play.

Even though they’ll pay out the same amount on average, two slots with an RTP of 96% might be completely different to play because they have different volatilities.

Example — If 100 players each bet £1 on Slot A (high volatility), there is £100 in the pot. The slot might hit, and one player wins £96, and the other 99 players win nothing. For the winner, the pay-out is huge (they only bet £1 and won £96), but they are the only winner.  This is a 96% RTP. Of £100 that was bet, £96 of it was paid out, to just one winner.

Example — If 100 players each bet £1 on Slot B (low volatility), there is £100 in the pot. The slot might hit a lot of times and 48 players each win £2. That’s a total of £96 paid out, but 48 players can call themselves winners. This is also a 96% RTP. Of £100 that was bet, £96 of it was paid out, but split between 48 different players.

The examples make it easy to see the difference in playing high vs low volatility slots. If you’re happy to hold on in the hopes of a big win, and get frustrated with little pay-outs, a higher volatility slot might be right for you. If you like the feeling of a win, no matter the size, look for a lower volatility slot.

Some sites will let you filter their slot catalogue by “Frequency of Wins”- this will let you choose a game based on volatility. You can always find a site that will let you demo the slot on freeplay mode to get a feel for the volatility.

Our Conclusion

To sum it all up, slot machines and online slots work based on Random Number Generators. These provide a completely random, unbiased result for each spin, completely independently of any results before it.

This means that although you may have heard people talk about finding patterns and studying slots to “work them out”, there really is no way to cheat or outsmart a slot machine to guarantee a pay-out.

There are a few things you can do to have a more successful experience.

  1. Understand how slots work

  2. This will help you be realistic in your play and avoid frustration when you feel a game is not being “fair”. Understanding that an RNG is a mathematical programme that is not “out to get you” will make losing feel more like a natural part of gambling, and less like a scam or trap.

  3. Only play at regulated, licenced sites

  4. Play at a gambling site that isn’t UK-regulated, and on your own head be it! There is no guarantee that they use approved RNGs, or that their slots aren’t fixed or rigged. If they are indeed a scam, the UK Gambling Commission is powerless to help you, as the site won’t be under their jurisdiction.

  5. Choose a game that fits your style

  6. Look at the RTP for slots you like, and see if you can find one with a volatility that suits you. You’ll have a much better time if your slot game pays out in a way that fits your expectations!

With all that information in hand, you can head out to find a slot you love, safe in the knowledge that you understand how they work!

Looking for a great slot game to enjoy? Browse our in-depth slot site reviews.