The mechanism of any slot machine is very simple: in order to win you need to collect several identical symbols on the same active line. These sets are called winning combinations and differ from slot to slot.

Experts of the leading provider of gaming content and software for online casinos, Slotegrator, suggest you an overview of all possible winning combinations in slots.

The diversity of slot machines in online casinos

Slot machines, or simply slots, are subdivided into several categories. All the types of slots are introduced in the table below.

Tipes of slots

You can find more information about slots and their characteristics here:

Traditional slot machines and video slots

Traditional slots and video slots are based on different technologies.  Modern electronic one-armed bandits use special software instead of mechanical reels. As a rule, there is only one payline in the classic slot machine. Although, sometimes its number can reach five.

Types of video slots according to the number of reels

Video slots can consist of 3, 5, 7, or 9 reels. Slot machines, where the number of reels is more than three, are already called multi-reel slots. These slots are based on random number generator and use modern software as well as have an interesting plot, creative design with amusing animations and sound effects. Extra bonus games are very common both on reels and additional screens.

Nowadays, multi-slots is the most popular type of slot games among online gamblers and operators as they suggest absolutely new game experience to players and bring good profit to vendors.

Types of online casino slots according to the number of winning lines

Winning line or payline, or betting line is a combination of symbols that results in a win, on a slot machine. Paylines can be of various shapes: from straight line to zigzag or trapezium. The bigger number of reels, the more options for combinations. Slots with such combinations are called line slots.

Modern slots suggest a great variety of paylines: from 1 to 1000 or even more. This number has a direct impact on the size of bets and the duration of the game.

Multi-line slots are the slots, which have more than one payline. The very first multi-slots had three reels; one payline was in the middle; the other two were above and below the middle one. If the winning combination is at least on one of the lines, the player gets the prize. You are supposed to make bets on every line.

In most slots, gamers can independently choose the number of lines with the help of special “Lines” function, but there is a small quantity of classic slot machines, where there are always 5 lines. You can choose at least one line, and the maximum depends on the number of lines in the slot machine. Thus, if the bet is made on two lines only, and the winning combination is on the third, the user wins nothing.

Usually there are such numbers of paylines:

  • One line

One line slots can be called retro classic. They are very close to those one line slots that were designed in the USA more than 100 years ago. These days, such slots are still popular as they have extraordinary gameplay. One line slots are available in the range of our partner Microgaming.

  • 3 and 5 lines

These machines are in fact an improved modification of the previous one-line slots. Usually they consist of 3 to 5 reels and have fixed paylines.

  • 9 lines

Nine line slots refer to the new generation of the slot machines. Usually, the users can choose the number of paylines, they want to bet. Moreover, such slots contain special symbols, scatter symbols and bonuses, including bonus games. They are considered as more exciting and thrilling than their predecessors.

  • 15 lines

As a rule, such slots consist of 5 reels and contain multiple symbols. Fifteen line slots have different bonuses and free spins. Free spins are played at the previously placed bet and fifteen active lines.  The gambler has a chance to increase the payout thanks to a bonus round. Therefore, 15 line slot machines are more thrilling than the previous ones. 

  • 20 – 100 lines

These slots are the most popular today. They suggest different interesting functions and vivid story lines. There are Wild and Scatter symbols, bonuses, which trigger additional bonus games. Often, these slots are connected to the accumulation system of jackpots, which means you can hit the jackpot. But the bets in this case are quite high.

  • 243 and 1024 lines

These slots are very alike with the previous category, except that the prize line means that the symbols on neighboring reels match. Due to this, there is a huge number of combinations making the game even more fascinating. Such slots require more investments, than the previous one with a smaller number of lines.

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How to generate and calculate the winning combinations in slots

You win in slots, if you gain the winning combination on the reels. You can build winning combinations in two ways: on particular paylines or within the whole gaming field. Earlier, you could easily calculate your chances on winning, all you needed was to know the number of reels and the quantity of symbols on them.

If the slot has three reels and twenty symbols, the chances to build the winning combination are the following: 20х20х20=8 000. This means that your chances to win were 1 to 8000.

For 5 reels slots, the chances of winning are even lower: 20x20x20x20x20=3 200 000; 1 to 3 200 000.

The chance to win in slots is usually marked in percent. The winning chances for one payline in the previous examples are the following:

  • 1/8000*100% = 0.125% for 3 reels slot;
  • 1/3200000*100% = 0.00003125% for 5 reels slot.

It is very difficult to calculate the chances of winning in modern video slots, because the number of paylines is very high, but the providers still mark the percent.

Groups of symbols and their cost

Modern slots favorably differ from their predecessors not only thanks to the quality of the design, but also due to the presence on the reels various symbols that possess a certain value.

All symbols can be divided into three groups:

  • Thematic. Usually images look like pictograms of the main characters; they dedicated to the plot of the game. They possess high multiplier factors and can bring nice wins. Thematic symbols are not so expensive in comparison with others, but appear on the winning lines infrequently.
  • Auxiliary. They often look like card signs. They are not expensive and you can frequently see them on the lines.
  • Bonuses. They give you special opportunities. They are considered to be the “titbit” for the gambler, as they give the access to additional rounds or free spins. They are estimated at a high rate.

Thus, the most valuable winning combination is a set of symbols that trigger bonus rounds. To activate the bonus game, as a rule, you need to collect on one line (sometimes on two) at least three bonus symbols. The number of bonus symbols on the reels is limited, so they cannot be received often.

Let's take a closer look at bonus symbols and how they form the lines in slots.

Wild symbol

Usually Wild symbols replace other symbols when the winning combinations are formed. In addition, some Wilds can give you a win right away.

Sometimes developers provide an opportunity of individual creation of winning matches. Such combinations are valued at the highest cost and bring good payouts.

In addition to the usual Wilds, modern video slots also suggest different modifications:

  • Stacked and Reel Wild symbols are the symbols that turn the whole reel into one big Wild. Stacked wild symbols look like one big reel-sized image. Reel wild looks like the multi-layer symbol, which fills in all the segments of the reel. 
  • Random Wild Symbol. The symbols appear on the screen in random order.
  • Expanding Wild is an image consisting of the adjacent symbols that look like several consecutive wild-symbols covering the entire reel.
  • Extra Wilds are the fixed symbols, which stay still during several spins. They are attached to certain symbols, which acquire the features of the Wilds.
  • Wild Symbol with multiplier increases the payout.

It’s not a full list of the functions and tasks Wild symbols can perform. Every day, developers come up with the new possibilities, making the gameplay even more fun.

Scatter symbol

Scatter symbols form different combinations of images, regardless of their location on the reels. If you have three Scatter symbols or more you get a free spin. Sometimes, two symbols are enough to get a free spin.

In addition to free spins, the Scatters give the player one more advantage: this combination is paid out additionally in accordance with the payout table. Therefore, the player receives a double profit.

Bonus symbol

Usually, bonus symbols trigger free bonus round or game. They give an opportunity to play a small tournament, where you’ll have to guess the pictures to win prize money. You need to collect a certain sequence of symbols in a line or just a required number of them in the whole field to trigger the bonus game.

How often the symbols appear

The probability of appearing landing symbols as well as their number in the field mostly depends on the total number of symbols in the slot. The bigger the number, the less matches there will be on the line and vice versa. It’s called “tapes” in modern video slots. The length of slots is programmed by the developer. For example, the number of special symbols in 5 reel slot can vary from 20 to 40. As a rule, Wild and Scatter symbols are put one time on a tape, the other symbols can be placed several times on a tape.

When the RNG stops every line, all the combinations are checked and if there are some matches, the gamer wins.

The cost of winning combinations

When the gambler makes a bet on the line, it becomes activated. The size of the bet does not always matter. You can win even with the minimum bet, if the winning combination of symbols occurs.

The bigger the total number of symbols, the less winning combinations there will be on the line. It means that to get a win you need to bet more often, but, as a rule, the payout is quite impressive.

The quality of winning combinations and volatility

Volatility is the level of risk in video slots. The frequency and the size of the win depends on volatility. If you win rarely but seriously, then such slot machines have high volatility. In slots with low volatility, wins occur often, but the size of the payout is small.

Volatility and the number of lines do not always depend on each other. A slot can have a large number of lines and, accordingly, a big number of winning combinations, but at the same time have low volatility and vice versa.


In modern online casinos, there should be a wide range of slots. Slots with the big number of winning lines and high volatility allow players to win more often. This is the best advertisement for any gambling office.

The Slotegrator company presents a variety of slot machines from more than twenty world-famous developers. Any slot can be easily integrated through API protocol into your online casino within a single session.

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