ICYMI: Online Slots are Based on Mathematic

ICYMI: Online Slots are Based on Mathematic

Who, what? Slots? Math? Yep, sorry but it’s true. If you thought you were switching your brain off just a little bit to have a spin and hopefully a win, you might be surprised to learn there is a whole lot of math going on behind the scenes.

There’s math behind many things that we might find surprising. There’s math hidden behind the beautiful artwork in mandalas. There is math behind the watch on your wrist. And there’s plenty of math behind the plays the coach outlines in the game of football that you’re watching. 

Despite 8-year-old you’s protestations, math is pretty fun if you look into it. Sure, it’s not that much fun adding up your purchases at the grocery shop to see if you have enough money to buy that extra packet of cookies that you are eyeballing. But beyond that basic, everyday math, there is a lot of excitement to be found in other hidden math.

So slots, with their chance to win big, present plenty of math lying just beneath the game’s surface.

As straightforward as no deposit bonus slots are to play, you might not expect them to be based on mathematics. But they are indeed so, and this article aims to delve deeper into the intricacies.


How likely is it that you will be a winner on the slots? Unfortunately, every time you spin to win, you have exactly the same chance as the last spin you made. And that’s probability – a certain flavor of math.

Probability is the likelihood of an outcome. If you have a set of five reels with 13 symbols, each reel might be a slightly different length. Here’s an example:

54 – 66 – 54 – 71 – 54

If you have just a one-line win open, could you count the probability of hitting five Aces on that line? Well, that depends on the distribution of the symbols across the reels. Let’s make it a little easier. How about if there was only one Ace on each of the reels? 

Then it would be

1/54 x 1/66 x 1/54 x 1/71 x 1/54

What does this add up to? A one in 737,876,304 chance of hitting that jackpot. Ouch!

Random Number Generators

Random Number Generators help slot machines keep these probabilities honest. That means that every time you spin it’s not based on the previous spin. RNGs are computer algorithms in slots that help give a random outcome to where each reel independently spins to. So while your chances to win the jackpot are one in 737 million, if you hit it, there’s nothing to say you couldn’t hit it again on the very next spin. Your chances of getting a heads in a coin toss after a series of seven tails in a row are just as likely as getting tails – no matter what our brains tell us.

What’s in an RTP?

The RTP – or return to player – is the math calculated for all possible outcomes of wins or losses in a slot machine, adding up how much the return is to a player on the dollar. So an RTP of 96% is 96c per dollar spent based on the probabilities. Whether you end your slots gaming session up or down from the input of your credit is all up to chance (aka probabilities!), though. You can’t complain that you were down 10c after putting a dollar into a slot game, that’s not how this math works.  

The math behind the bonuses: The wagering requirement

If you’ve ever grabbed an online casino bonus, you may remember the number called the wagering requirement. This number is a multiplier, like 20x. This is pretty easy math to remember. Your bonus times the wagering requirement is how much you have to actually bet before you are allowed to cash out your winnings on that particular bonus. This is also why it’s good advice to pick a bonus with a low wagering requirement!

Game houses employ mathematicians to come up with new games

Entirely new games and features are developed first by mathematicians – not artists or storytellers  – which is why game houses employ mathematicians to keep their lineups fresh and stand out from the competition. For instance, if you take a look at the jobs board for Aristocrat, you’ll see several mathematician roles listed under the Game Design category. These people come up with probabilities tables to help deploy things like floating reels to make the game more fun. While the artists and animators make it look appealing to you, there are people behind the scenes working some serious math to make sure that new feature complies with game regulations from the authorities.

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