Rules of Slots

Rules of Slots

The popularity of slots in online casinos is evident for two reasons: simple rules and low entry threshold; you do not need any special knowledge or skills to play, as results depend entirely on luck and a random number generator. The only thing you can influence is the bet size, but at the same time, there are specific rules of slots in the USA that concern their mechanics and options available. Understanding these features can help you choose the best game, so in this article, let’s look at primary slot options.

How Do Slot Machines Work

Any slot machine is a field consisting of a certain number of reels and rows of different symbols; once you have decided on the bet size, you need to press the button to start the spin, and its result determines whether you have won or lost.

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If, after stopping the reels, you can see a line of identical symbols on them or any other condition for getting prizes is fulfilled, you get a payout. Otherwise, you lose the cost of one spin and can continue playing.

Slot Machine Rules Guide

Among all game categories available in most casinos, slots are the most popular thanks to their simple rules and absence of the need to make complex decisions, so these games are ideal for both beginners and experienced users. However, despite the simplicity, each slot game offers a unique gaming experience with the help of different mechanics and features. If you want to understand what happens on the reels and what to do to get the prizes, you should learn the basic concepts.

Basic Rules & Terminology

Gambling studios develop casino games and slots rules; they not only create slot machines for online casinos but are also engaged in their setup and technical support. Gambling sites have nothing to do with slot machines, as they only act as an intermediary, giving customers access to games.

Providers’ servers host slots, so neither players nor online casinos can affect their characteristics and work parameters.

The first thing you need to do to understand game principles is to learn the terminology. Many terms may be unfamiliar if you have never played slots before, so now it is time to fix it.


A random number generator is responsible for everything occurring on the playing field; it determines what symbols appear on the reels after rotation, as well as their quantity and order. All slot machine rules are based on RNG work; that’s why all outcomes are unpredictable.

To confirm the random number generator is fair, many gambling providers get special certificates issued by reputable digital labs, such as eCOGRA and iTech Labs.

The RNG determines spin results in a split second after you press the Start button, and previous results have no effect on the next ones. This means that the chances of getting a payout do not increase regardless of the number of unsuccessful bets made.


All symbols in slot machines are located on vertical reels, which begin to move after launching a spin, and their number can vary significantly. The most common option is 5 reels, but some modern slots have many more: 8, 10, or even 12.


The primary condition to get the prize in most slots is to form a sequence of identical symbols on the reels, which can be straight and convoluted. Slot machine game rules display the number of ways to form payable combinations.

Slot paylines
In some slots, you can change the number of active lines

Theoretically, the more lines are involved, the more payouts you get, as it becomes easier to make a combination of the same symbols, but in reality, this is not always the case. Usually, when you increase the number of active lines, the total number of symbols also grows; in addition, the more lines there are in the slot, the less it pays for each of them.

Wild Symbols

Wild is a universal symbol that can replace any other image when forming a payline; it replaces the missing symbol and allows you to get a payout corresponding to the picture value. If you manage to collect a combination formed from wilds, you usually get the biggest prizes.

Both new and classic slot machines use these mechanics, and at the same time, wilds can have various additional options according to particular slot game rules.


Expanding wilds can occupy several cells or one reel at once, and this allows you to form a larger number of combinations in one spin. Many popular slots use these mechanics; Divine Fortune is an excellent example, where the symbol of Pegasus can fly up and occupy the entire reel or activate a series of re-spins.


Usually, stacking wilds work together with multipliers when each increases the total payout per line; these multipliers are often combined with each other. For example, two wilds of x2 increase the prize money by 4 times.

Scatter Symbols

In most cases, this symbol does not take part in paylines formation and does not bring any prizes, but it is necessary to activate a series of free spins. When the required number of scatters appears on the reels, a bonus game becomes available; usually, you need to get at least 2-4 of these symbols for one spin.

Casino scatters
In slot machines like “Book of…” scatter acts as a wild

Use the Help section to view the exact number of scatters needed to activate free spins and additional mechanics provided by this symbol.


Each slot machine symbol has its own value, and you get more funds for collecting rare images, but to get larger prizes, you can also use multipliers, which can increase your payout on a particular line, for a single spin, or in a bonus game.

Multiplier mechanics have many variations: they can be one-time and cumulative, general and for specific symbols, random and guaranteed, and so on.

Payout Tables

You can find a list of all symbols available in a particular game and prize amounts corresponding to them in the rules of slot machines. It is necessary to open the informational section using the main menu or pressing the “i” button. Each symbol has its own value, and the rarer it is, the bigger prizes it brings.


The random number generator works according to the RTP criterion: the theoretical percentage of returns to players. The most popular slots with high RTP are listed below.

Sweet BonanzaPragmatic Play96.48%
Gates of OlympusPragmatic Play95.51%
Hand of AnubisHacksaw Gaming94.32%
Release the KrakenPragmatic Play95.5%

This criterion determines how much money from all bets made customers will receive as payouts in the long run. For example, if RTP is 96%, then out of $1,000 invested, gamblers will get $960, and the remaining $40 is the casino’s and the provider’s profit. High RTP brings more profit in the long run, so if you do not know what to play, choose slot machines with high return percentages.

RTP applies to the total amount of money invested by all players, so everyone can make a profit or hit an enormous prize.

The average RTP value for most slots is between 93 and 96%; you can see the exact RTP in the game description on its developer’s website.

Volatility (Hit Frequency)

This criterion is rather abstract and does not have an exact numerical value; it characterizes the slot riskiness and affects the payout frequency and size.

Slots with high volatility can offer a more extended series of wins and losses, while payouts can be less than the initial bet and many times more. These slot machines are likely to give maximum payouts: you can win a lot, but at the same time, the risk of loss is significant. Low-volatile slots pay more often and help you keep your bankroll, but it is more challenging to get a large payout.

Table of Content

Payouts provided for forming combinations of the same symbols is the basic mechanics, as slot machines can also feature many other options. For example, sometimes you get prizes not for lines but for the number of identical images, regardless of their location on the reels. To understand how all supported mechanics operate, open the slot machine game rules and find the tab with the payout table.

Coin Value & Bet Size

The only important decision you make when playing a particular slot is to determine the bet size; there are two ways to change it:

  • The choice of the total bet size. There is usually a particular fixed set of values.
  • Changing the number of lines and coin value. In this case, changing the bet amount goes slightly differently as you determine the coin value and the number of coins for each line. For example, if a coin is valued at $0.1, and you bet one piece per 20 lines, the total bet is $2.

You can use arrows in the control panel to change the bet size or choose values from the specific table.

Winning Combinations

Payouts can occur on a line or for the total number of identical symbols on the reels. In the first case, you need to form a particular sequence from images that come up, and in the second case, only their number on the reels matter.

Slot odds and paytable
You can check symbols value and potential payouts in the paytable

If none of the conditions for prizes accrual is fulfilled after the spin, you lose your bet.

Rules of the Best Slot Bonuses

To make gameplay more interesting, gambling studios add additional bonus features to their releases. Some gamblers play particular slots just to activate bonus options because, in these rounds, potential payouts are much larger than in standard games. There are two basic types of bonus features.

Free Spins

This is a series of free spins, during which you can activate additional mechanics, such as multipliers, expanding and sticky wilds, increased number of reels, and so on. You do not have to pay for them, and after you run out of free spins, you get the total amount of prizes obtained within it.

Bonus Rounds

The difference between this feature and free spins is that the game takes place not on the standard slot’s playing field. Usually, this is another location where you need to open chests with random rewards, spin the wheel of fortune, choose different items, and so on.

How to Calculate Spin Cost

If the bet size is immediately selectable at the bottom, you can also see the current spin value there. If the slot uses a coin mechanic, you need to multiply coins’ value by their amount per line and the total number of active paylines to calculate the spin cost.

Rules of Slot Machines With Progressive Jackpots

You can get even more emotions and a gambling experience by playing slot machines that participate in progressive jackpot raffles. In these slots, the prize pool constantly increases because it is formed from all customers’ bets; after someone hits it, the jackpot is entirely or partially reset, and the accumulation occurs again.

Divine Fortune by NetEnt
In the Divine Fortune slot, you can win several jackpots

Providers determine the conditions of winning the jackpot, but usually, to get it, you need to reach the bonus game, where you will have an opportunity to become a millionaire.

How to Choose an Online Casino Site to Play Slots

Now when you have learned everything about the rules of slot machine games for US players, it is time to talk about an equally important topic because to play for real money, you have to choose an online casino and register. Instead of creating an account at the first site you come across, it is better to pay more attention to checking casinos; we recommend using several criteria:

  • Legitimacy. Check whether the casino has a license issued by the state regulatory commission. Without this document, a gambling site cannot be considered reliable, and it is not safe to register on it.
  • Number of games and providers. Pay attention to the total number of games available in the catalog, as well as the list of particular developers the casino collaborates with.
  • Bonuses. Check the availability of a welcome bonus for your first deposit if you want to make your start easier. If you are going to get additional benefits constantly, pay attention to reload bonuses, cashback, loyalty programs, and available tournaments.
  • Payment methods. Check what deposit and withdrawal tools are available, the casino payment limits, and how long it takes to process financial transactions.
  • Customer support service. You need to know how many ways to get in touch with support agents on the website and how quickly the support team responds.

Also, if you play on a smartphone, make sure the casino has a convenient mobile version of the website or a downloadable app.

Top Tips on How to Play & Increase Winnings

You cannot affect the game results because the random number generator determines them. Everything depends on luck, so do not expect any recommendations to allow you to make a profit.

No strategy can guarantee winnings; gambling always involves risks, so do not spend money you are not ready to lose.

However, you can use some tips to minimize risks; some of them allow you to keep your bankroll for a long time.

Follow Casino Etiquette

Before registering at a particular website, be sure to get acquainted with its rules and conditions, as each online casino has a list of mandatory requirements, and non-compliance with them can lead to a ban.

For example, only adult users are allowed to gamble; in addition, you can have no more than one account. All personal data specified when registering and filling out a personal account should be valid. You can withdraw funds only on your own cards and accounts, and to confirm your identity, it is necessary to provide photos or digital copies of your ID or another document.

Money Management

Never bet all the money for a few rounds; divide your bankroll into several parts for at least 50-70 spins; otherwise, the dispersion effect will be too strong. The higher the slot volatility, the more spins your balance should cover.

Also, we do not recommend increasing the bet size sharply to win back quickly, as this will only make the game riskier. Calculate the optimal spin value initially, stick to it throughout the game session, and increase it only if you win and your bankroll becomes more significant.

Classic Slots vs. Video Slots

Nominally, depending on the slot machine rules and other criteria, we can divide all games into classic and modern. The first category is rather narrow: these slots have a simple design, lack of complex mechanics and features, and low or medium volatility. The number of lines in classic slot machines rarely exceeds 20, and as for additional mechanics, there are usually only wilds and free spins.

Classic slots
Classic slot machines have a simple design and interface

Video slots are those games that do not fall into the classic category; there are no exact restrictions for them, so they can have a non-standard playing field, modern design, complex features, brand-new mechanics, and so on.

Rules of Slots for Different Countries According to Legislation

States are responsible for regulating online gambling in the USA, so in one part of the country, online casinos may be unavailable at all, while in another part, there can be a bunch of reputable and legitimate casinos.

Moreover, to operate in the USA, a gambling site must be approved by the local gambling commission, while in other countries, it is enough to have a license from one of the international regulators.

Check the casino rules to know in what regions a particular casino is available.


The same slots have the same mechanics and features regardless of the specific online casino you play.

This is a popular mechanic with which any reel can have a different number of cells for a particular spin.

It depends on the maximum payout of a specific slot machine; some of them allow you to get a prize of x300,000 from the initial bet.

Yes. This possibility is available in many slot machines; you can pay a certain amount of money, usually the value of 100 spins, to instantly go to the free spin round.

Yes. You can open several slot machines at once, even if you play in one online casino.

Publication Author
Donald Peterson
Author of articles
Donald Peterson is an avid gambler from Edmonton, Alberta, who also writes about his experience with casinos. He’s been in the business for over 10 years, following the ever-changing industry landscape. His articles are aimed at helping beginners with choosing casinos, suitable games, and strategies.
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