Slot Machine Payouts

If you’ve ever won on a slot machine, I’m sure you were ecstatic to claim your money. You watched the credits won display climb until you saw how much you had won. You probably didn’t think much about how that amount was calculated and what your odds of getting that payout were. I bet you thought even less about the mechanics that went into the winning symbols you got.

Understanding the Basics

PayoutsKnowing these things will help you to better understand slot machine payouts. With this knowledge, you can make an informed decision about which machines you want to play. You can also determine if you are making a bet that gives you the most value for your money. All of these aspects are important in making the most of your slot machine experience.

How the “Stops” are Determined

A slot machine stop is, you guessed it, the position and corresponding symbol that is showing on the slot machine reel at the end of your spin. There are a lot of calculations that go into selecting which symbols you will get on your spin.

Just because there are only 8 symbols available on a particular game, does not mean the reels only have 8 stops to choose from. A mechanical slot machine will usually have 22 stops, while a video slot can have as many as 256 per reel.

Because of the high number of available stops per reel, the machine software is able to create countless possible outcomes. This is why you will see lower paying symbols occur much more frequently than the jackpot symbol. Even though the outcome is completely random, the odds are not equally distributed between the symbols.

Random Number Generators

The outcome of a slot machine spin is determined by a microchip installed within the machine called a Random Number Generator or RNG. The Random Number Generator works on complex algorithms, producing a random result several billion times per second. The number on the RNG at the moment you push the spin button determines whether you’re walking away from that spin with a jackpot.

Weighted Reels

Have you ever noticed that you “almost” get the jackpot frequently? Many people think that this is a sign that the jackpot is going to hit soon. As we just learned, the Random Number Generator determines a spin outcome and there are no patterns.

That does not mean there is no strategy on the part of the game designers to make you feel like your chances of hitting the jackpot are higher. They accomplish this by using weighted reels. Basically, this means that there are more high paying symbols available on the first reels.

You are much more likely to get a jackpot symbol on the first and second reel. There are fewer available jackpot symbols on the later reels, making the jackpot much less likely. You still see the symbols come up frequently, giving the illusion of a better chance at winning a big payout.

The outcome is still completely random. With more possibilities for high paying symbols on the first couple reels, the Random Number Generator is more likely to select them. Each spin is independent of another, so seeing the jackpot symbols come up frequently is not a sign of an impending jackpot.

Reading A Slot Machine Pay Table

Most slot machines will have a pay table available for you to view. It will clearly state the amount of the payout for each winning symbol combination in the game. This includes information on wild and bonus symbols.

The pay tables are usually easily accessed from the main screen of the slot machine game. You will see a button saying “payouts” or “pay table”. Sometimes the pay table button is accessed through the rules section of the game. If you don’t see a pay table button on the home screen, the rules button would be your next step. If you can’t find any pay table information, you can ask the casino for the information.

There are usually multiple pages to the pay table information. The first page will contain your payout amount for each symbol and for each winning combination of that symbol. For example, it will state that 2 cherries pays 2 credits, 3 pays 10 credits, 4 pays 50 credits, and 5 pays 100 credits. Any winning combination will be listed with its payout amount in the pay table.

On the additional pages will be wild, scatter, and bonus information. This includes which symbols represent each available additional feature. They will include the details of what the additional feature involves also. You should also be able to find what the paylines are and the total number of them.

Keep in mind that when reading a pay table, the amount shown for a win is displayed in credits. This must be multiplied by the denomination you’re playing to get a currency amount. For example, if you are playing a $.25 machine and you get 4 Aces for 50 credits, you have won $12.50 (50 x $.25).

Calculating Payout Percentages

This can get a little tricky. The math is slightly complex and figuring out the weighted probabilities of each symbol and reel can be difficult. In fact, for this article, we will not be calculating the odds of hitting specific jackpots. We will cover a basic overview of how you can calculate this for yourself, and also how to use the information to better understand your payouts.

Probability of Winning Combinations

This information is available on PAR sheets if you can find them. In order to calculate the probabilities of the winning combinations, you will need to know the details of how many symbols are on each reel and how they are weighted. The information can be difficult to find.

To calculate the probabilities of winning combinations, you will need to know the total number of positions on the reels, and also how many of each symbol is on each reel. Remember this is usually not uniform, as the reels are typically weighted. If you had this information, the probabilities would be calculated as follows:

For purposes of this calculation, we are looking at a 3-reel slot machine, with 22 stops on each reel. Let’s say there are 3 cherries on the first reel, 2 on the second, and 1 on the third.

Reel #1 Reel #2 Reel #3 Total
Cherries/# of Stops 3/22 2/22 1/22 0.05635% or 1 in 1,775

You can use this same formula to calculate all the odds for all winning pay lines on the slot machine game. With this information, you can take your knowledge a bit further and figure out how much of the money wagered is expected to go to the house.

PAR Sheets

PAR sheets will have all the information you need to do your own calculations, in addition to the ones already on the PAR sheet itself. These are considered insider information and are not easy to find. They are supposed to be kept confidential, though the information gets leaked often.

If you are able to locate a PAR sheet for the game you are trying to research, you will be miles ahead in the calculations of house odds and probability.

House Advantage Percentages

If you are able to gather the information to calculate the odds of all the winning paylines, you will be able to calculate the house advantage. This is also referred to as the slot hold percentage. The house advantage is the percentage of money the casino will take from players on average.

To calculate this, you will need the odds for all payouts and the pay table information. It is calculated as follows:

Probability Payout Probability x Payout
0.0005638% 1000 0.564%

We used the same example as above and used a payout of 1000 for getting three cherries. To obtain the slot hold percentage, you need to do this calculation for all winning combinations. From there, you will add all of the percentages from your probability times payout column together. This will give you a figure usually between 75% – 99%.

So, what exactly does this calculation tell you? The percentage you have calculated is the amount of money the slot machine is set to take from the player, on average, over a long period of time. If its 85%, this means the slot machine will take 15% of all the money that is played through it. Due to the Random Number Generator, shorter stretches can be especially variable. The longer the period of play, the closer your losses will resemble the house advantage percentage.


There you have it; everything you need to know to understand slot machine payouts. Always remember that all slot machines are programmed to take your money in the long run. House advantages matter, as they determine how fast you will likely lose.

However, keep in mind that since all slot machines will eventually be a losing venture, the main factor in deciding which ones to play should be fun. Pick the game you enjoy the most.