Casino Slot Machine Elements

Normally, the slot device itself is composed of a few important components, similar for every slot machine around the globe. Some of them include the reels, paylines and paytable. We will discuss each of these elements and take a look at the basic terms, along with the specific slot functions. Although the majority of slots are standardized, there are some machines, which are more complicated and we need to review them additionally in order to help you fully understand how they work.

Reels are essential for the slot machine, since they are the actual mechanism spinning the symbols and raising the players heartbeat. Their technical term is step reels and slot machines have at least three of them. The most popular slot machines are those with three or five reels, but there are even ten reel machines called Fat Berta on the name of the First World War super heavy weapon.

There are a few steps and stops for each reel, which mark the place where it can land after spinning. These stops are symbols, such as cards, fruits and diamonds, but they can be practically everthing. They can even be empty.

At the very beginning of slot industry, reels had only ten symbols, but technological development drastically increased their amount. The manufacturers wanted to add more symbols for more potential combination. This allows them to offer bigger wins and attract more players.

For example, let’s calculate the amount of potential combinations of a slot machine with 3 reels and 10 symbols for each.

Combinations = 10 x 10 x 10 = 1,000

This means that the chance to hit the rarest combination is 0.1%, which decreases the chances of a win for the player. Machines are developed to make profit for the company operating them. Later on the typical slots consisted of three reels with 20 symbols each, i.e. 8000 combinations. This improvement is also a limit for operators restricting them from big Jackpots. The development of electronics and microprocessors makes the potential combinations much more. For example, a digital reel can have 256 symbols and 16 million of combinations possible.

These calculations up to now were only about slot machines with three reels, but like we mentiond above, the one-armed bandits can reach up to ten reels and the total number of combinations then would be 1,20892582×10²⁴! Keep in mind that the number of symbols doesn’t restrict the chance of a win for the player. All it does is increase the potential combinations. This provides the manufacturers with extra flexibility.

The payout chances are determined by the frequency of winning combinations you hit. If the chances of a winning combination are quite slim, the payout would be smaller, too, and vice versa. Having lots of combinations allows the players to win millions with simple bet of 1 EUR. The frequency of hitting and payout are set by the manufacturers, together with the specifications of the casino operator. Besides, all the data can be reset anytime just by changing a computer chip.

What does a payline mean in slot games?

The central horizontal line at the screen of the slot machine is what we call a payline. In order to win a certain spin, the winning symbols have to align on the payline.

At the dawn of the first slot machines, there was only one payline at the center of the screen. Their number increased in time to three, five and more. Some machines with five reels even have 25 paylines or more. In order to activate them all, though, you have to make a separate bet for each. Generally, you bet one credit per active line, but some machines accept a few coins per payline.

Casino slot pay lines

What is a paytable in casino slots?

You will learn there all the winning combinations and the potential payout, according to your current bet. Special combinations are also listed here. The paytable can also show if the machine is progressive or not and the total Jackpot available at the present moment.

If you are not well aware of progressive slot machines, you can check another article of ours and learn more. Let’s just say for now that progressive machines are interconnected to the same Jackpot, so the prize is increasing pretty fast.

What does a casino paytable look like?

Coin tray of casino slots

This is probably the most favorite component of the slot machine for every enthusiastic gambler, because that is where the coins come from. The coin tray is at the bottom of the machine facing the player. Once you press the Payout button, it start spilling your wins all over. Of course, this is a part only available in physical casino. Online slots are missing this essential and exciting advantage of the machine.

Coin tray of casino slot machine

Slot lever. Why is the slang term for casino slots called One-armed bandits?

It all starts with the lever that triggers the reels spinning. It is on the left of each slot machine, but today it is not a necessity, more like an accessory for being authentic. Although the lever used to start mechanically the reels, all you can do with it now is to start the software that gets the reels going. That is why the machine is called one-armed bandit. The lever is the arm and the slot machine is the bandit. The last word comes from the fact that casinos aim to gain from players, so they “rob” and they are “bandits”. Now you get it – one-armed bandits.

Play buttons

Let’s get to know the most common buttons in slot machines. Note that the names in particular can vary for each model and manufacturer, but in general, the functions are similar.

Spinning the reels

This is the triggering button. Once you press it, the reels start spinning.

Maximum credit play/Maximum coins bet

Regardless of its specific name, this is button that gives you the chance to bet the maximum credits allowed at the machine. This means that if the slot machine allows a maximum bet of five coins and the player presses the button, five coins will be deducted from the credits of the player and the reels will start moving.

Bear in mind that this button is active only if the player has credits in the machine. If that is not the case, then you simply have to insert more coins before the button is active.

Playing with two credits, Playing with three credits

Such buttons usually indicate that the given slot machine takes only two or three credits for a maximum bet. So by pressing the button, the player would produce the same result of pressing a maximum credit play/maximum coins bet button.

Playing with one credit

This button allows players to bet only one credit per spin. It can be found on any slot machine, which guarantees that various types of players have the chance to try it out. Let’s not forget to note that in comparison to the Maximum credit bet button, this one doesn’t start the reels going. The action begins when you pull the lever and press the Spinning the reels button.

If you press the button twice, the slots will add extra credit to the next spin, etc.

Send button

Generally, this button informs the machine that the player has finished betting and they would like to either move or stop playing at all. Old one-armed bandits start paying the credits remained in coins once you press it. New slot machines are different, though, they just issue a ticket to the player, so that they can use it when requesting to get their wins.

Cash out button

This button is on the left of the button display and when you use it, the red light above the machine indicates to all casino employees that the player wants to exchange their money in coins.

Slots display

There are a few displays for each machine. They are usually in front of it, but although a different manufacturer might have chosen a different location, just keep in mind that the basic information will always be visible for the player.

Credits or coins played

Remember to always note the exact amount of credits you bet for each spin of each slot. In case the display is showing number 3, then you bet three credits per spin.

Slot credits

This is a display showing the number of remaining credits of the player.

When the indicator reaches zero, then player has to insert more coins in order to play. The number of credits can be increased by either winning spins or inserting additional coins in the machine. Each credit represents a certain value. In case the player is at 25 cent machine, for example, and inserts a bank note of 10 EUR/USD?GBP, the credit display will indicate that there are 40 credits. Also, if a player bets 3 credit during their next spin, the display will change to 37. On the other hand, the screen will show 47 credits if the player wins 10 afterwards.

Just like we already mentioned, the display doesn’t show you the money you bet, but the number of credits you bought with that money. For example, a banknote of 10 EUR inserted in 1 EUR slots will equal 10 credits, but in another machine of 5 cents it would be 200 credits.

Pressing the Play button with one credit will automatically deduct one credit off the player’s remaining credits and the Play button with maximum credits deducts the maximum amount of credits allowed per spin at a certain machine.

There are two ways you can use your credits: by playing and losing them all or by pressing the Payout button, so that the machine can issue a ticket. Take this ticket – it is the actual amount of money you can exchange at the pay desk.

Paid to player

This screen shows the number of credits won during the last spin, which would be added to the credits of the player.

Insert a coin

This message displayed shows that nobody is currently playing the slots and that anyone can start playing by inserting coins or banknotes in the machine.

Mistake code

This message is shown only if the machine cannot function right and needs to be checked by a technician. The display shows series of numbers and codes that explain the nature of the problem. That way the staff member responsible for fixing the machine can take action as soon as possible.


Although most slots are entirely transformed by technology, there are still some traditional symbols that withstand the test of time. You can still see the Bell, symbol of freedom, which appeared on the very first slot machine created in 1899. It is often used in popular slots. Other classic symbols include cherries, lemons and Lucky 7s.

The Bar symbol is another classic survivor. Nowadays it is often modified to double bars, triple bars and so on.

Although many classic symbols are still available, much more were born in the imagination of slot machine developers. There is a huge variety of fruits, numbers, cars, logos, letters, animals and many others. You can use practically anything as a symbol.

Wild symbols of casino slot

Wild symbol has become quite popular among modern slots and it can be used as a replacement to any other symbol in order to create a winning combination. In case the player gets two matching symbols, e.g. cherries, and a Wild symbol appears on the same payline, the slot will credit a payout to the player, according to the combination of three cherries.

The Wild can sometimes act as a multiplier, too. In case the player gets two cherries and a Wild, the machine will pay the amount corresponding to three matching cherries, as we told you. If the Joker is also a multiplier, then the payout will get double, triple or quadruple.

What is Scatter in casino slot game terminology?

Scatter is a symbol that awards you with extra wins. Depending on the slot game, Scatter can multiply winnings, stretch all over the reel or award you matching symbols and winning combinations. Scatter symbol is similar to Wild.

Any Bar symbol

This is another popular symbol typical of classic slots with three reels. There are single, double and triple bar and Any Bar symbols can be combined in order to form winning combinations.


Slot machines often show empty symbols when there is no potential to win.

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