Slots Math

Any beginner will certainly be interested to know how modern slot machines work. This article will focus on such important characteristics of slot machines as payout percentages and dispersion, which will help beginners to understand the principle of winning in online slots. Unlikely that this information will make you a millionaire in one second, however, having familiarized yourself with it, you will get a complete idea of ​​how to choose the online slot correctly in terms of potential chances to win.

Payout percentage

The first characteristic that you need to pay attention to when choosing an online slot is the payout percentage or, to put it in scientific terms, the expected payoff. The payout percentage is a certain part of the total bets amount in the slot, which is guaranteed to be returned to the players in the form of winnings. The higher this figure in the gaming machine – the better. The payout percentage for each online slot is different: the most generous machines offer players 95-98% payout, but there are models with an indicator below 90%. It is easy to calculate now that there will be from 2 to 10% casino share from all bets. These parameters are set by the manufacturer when developing an online slot and remain unchanged. However, another question immediately arises: can the owner of an online casino change the payout percentage, which means, “tweak” the online slot?

Theoretically this is possible. For example, you can change paytable or the layout of the reels by removing a few expensive symbols. In the first case, the changes will soon be noticed by attentive users, and in the second, the gaming machine will have to be reprogrammed altogether. Do not forget that the gambling software of online casinos is periodically subjected to a number of checks by independent organizations, and the test results and payout percentages are laid out on the Internet for all to see. It is unlikely that a legal online casino or a world-famous provider will sacrifice their reputation for a couple of extra percent. The conclusion suggests itself. Choosing legal casinos with reliable software, you get high-quality online slots with guaranteed correct percentage returns.


One of the most important characteristics that you should pay attention to when choosing a gaming machine is the variance value. This concept came to gambling from higher mathematics. If the payout percentage is essentially a mathematical expectation, then the dispersion indicates the degree of deviation from the mathematical expectation. If we translate this definition into the language of gambling, this is the degree of risk when playing in one or another online slot. The lower gaming machine variance, the more often it will delight players in small payments. A highly dispersed slot is the opposite. If the slot has issued a large jackpot, then be sure – the next payment won’t be soon.

Why should the player know the value of dispersion? It’s pretty simple. Take two online slots with the same payout of 98%. The first distributes payouts in small pieces at short intervals, allowing players to win systematically. The second slot after a hundred spins gives only 10% of the sum of all made players’ bets, and only a hundred first time gives a big win. Of course, in the second case, the risk of gamble away is much higher than in the first. Moreover, it will be a shame if a frustrated player leaves the slot machine with nothing, and the next user who decides to play the same online slot will hit the mega jackpot from the first spin. This example shows that the chances of staying in the positive are much higher for a player who favors a slot with a low dispersion.

How to determine dispersion

All online slots can be divided into three categories: low, medium and high variance. The most popular at the moment are gaming machines with averages, as they represent an intermediate option between low-dispersed and high-dispersed slots. It is worth considering that manufacturers never specify the value of the variance, although you can define it yourself on several grounds.

Paytable. The easiest and most effective way to determine the dispersion value. If the maximum payout does not exceed bet increase in 5,000 times threshold means that this is slot with a low dispersion, up to x10,000 means that slot with an average index, above x10,000 – is a sign of a high level of dispersion. You also need to compare the indicators in case of three, four and five identical symbols. A small difference in the coefficients indicates low dispersion. Consequently, a large gap in the amounts suggests that the slot refers to models with high variance. The presence of wild, scatter and other bonus symbols most often indicates a medium and low variance.

Game in demo mode. Most online casinos offer their customers the opportunity to play slot machine emulators. Thus, you can design this or that model absolutely free by yourself. For example, if during half an hour, the machine has issued several winning combinations with a low and average payout rates, then you have a slot emulator with low or medium variance. If during the entire testing period the emulator has issued only one or two expensive combinations, or you feel that you are constantly leaving in the negative – this slot can be safely attributed to highly dispersed. But do not trust the demo version. Software providers themselves admit that from time to time they use another random number generator for demonstration slots to show all its capabilities in a short period of time.

Progressive jackpots. If the gaming machine is connected to the network with a single growing jackpot, then the dispersion of this slot will be extremely high. On the other hand, if you like to take big risks and are not limited in means, then a progressive jackpot slot machine is what you need.


The main thing is to understand your ultimate goal and evaluate the means available for this. We advise owners of a modest bankroll to turn their attention to a small dispersion slot machines. Playing these slots, you will not only be able to stretch the fun, but get a chance to earn some extra money. If you can afford a large number of spins at maximum bets and like to take risks, then there is no better option than progressive jackpot slots.

See also:

  • Paytable
  • Slot types