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Slots or slot machines are coin-operated gaming machines that generate combinations of symbols at random on a dial. Certain combinations will produce a win and payout. Slot machines are known by different names across the globe, from fruit machines in the U.K. to pokies in Australia. No matter what they’re called, they are leading revenue generators for almost all land-based and online casinos. You are probably wondering what slot machine odds are or how to win at slots, but first, let’s look at the inner workings of the machine.

Free Play Slots

Play slots at Bovada.

How Does a Slot Machine Work?

There’s one primary element to modern slot machines: the random number generator (RNG). As soon as a slot becomes active, this function starts producing random numbers at an inhuman rate (usually hundreds per second). 

The instant a player presses the spin button on a slot machine, the RNG grabs the most current series of digits and uses them to determine the outcome. While the spinning symbols present the illusion that the final result is determined one reel at a time, it’s actually over as soon as the player decides to press the button.

Even though winning symbols are selected at random, some are programmed to appear more often than others. If this wasn’t the case, wild and bonus symbols would turn up at a much higher frequency and result in a major loss for the house. This does not have an impact on slot machine odds (more on that later).

House Edge

When thinking of how to win at slots, you’ll want to learn about the house edge because on most slots it ranges from six to 15 percent. Land-based slots have to pay out at a minimum amount as determined by their state or country, while their online counterparts tend to be less regulated. If you stick with a reputable online casino that uses software from a leading provider, you should be OK and have a proper house edge. If you play free slots for fun, you don’t have to worry about the house edge.

What are Slot Machine Odds?

When it comes to slots games, there are so many variations out there that figuring out the odds is nearly impossible. Instead, slot machine odds are expressed in the form of payback percentages. As a player, you want to search for games that give you the biggest payback percentage you can find and online that should be at least 99 percent or better. Again, if you choose to play free slots for fun, you don’t have to worry about slot machine odds.

For nickel slots games, the average payback percentage in a live casino is 92.5 percent. The quarter machines pay back an average of 94.1 percent, the dollar machines 95.9 percent, and the high-stakes $5 games pay back 98.4 percent. Online the overhead is much less than a live casino, so payback percentages can be bigger without the house feeling the pinch.

Online, the payback percentage of most casino slots games is around 99 percent. With so many casinos to choose from, you have to take the time to find the best games with the highest paybacks. It may not be a big difference during one session, but over the longer term of playing the game, it will add up to a significant amount.

On average, in a slots game with a payout of 90 percent where a player is taking 10 spins per minute, a player will need $9 per hour played on a nickel machine, $45 per hour on a quarter machine, $180 on a dollar machine and $900 per hour on a $5 machine. Online payout rates are higher than 90 percent but you’ll often play faster online, so these numbers should be good guidelines.

Progressive Jackpots

Progressive jackpots can increase the payback percentages of slots games because the jackpot amount considerably increases the potential win. If the jackpot is big enough, the return on a game can easily exceed 100 percent of the intake, thus giving the players a positive betting situation. 

Just remember that when it comes to progressive jackpots, the bigger they are, the better the payback percentage. Wait until the jackpot has grown to a good size before playing, and make sure that you remember to play the maximum bet on any progressive jackpot game you play. If you don’t play max bet, you don’t qualify for the jackpot, and your payback percentage will go way down.

Is There a Special Slots Strategy I Can Use?

If someone offers to share a slots strategy with you, prepare to be disappointed and don’t give them any money. There is no system or trick for beating slot machines. Anyone who says they know how to win at slots is lying. Modern slot machines are equipped with RNGs that ensure all spins are independent of one another, so it’s impossible to predict what symbols are going to turn up on the reels. If you think you have the best slot machine odds, there’s also the payback percentage (see above). Even if it’s a generous number like 97 percent, long-term play should still result in a three percent loss.

Slot Machine Myths

There are so many myths surrounding slot machines that it makes people think they’ll beat the game after playing a few spins. Don’t believe the hype. As mentioned, no one can tell you how to win at slots. In order to get the most out of your money, and have fun, avoid falling prey to the following myths:

1.    Always bet the maximum: Some players insist that you must wager the maximum amount as it gives you a better chance of winning. This is false, as the RNG does not take the size of the player’s wager into consideration. The only time we can suggest risking the maximum is on progressive slots, as the rules usually require such a bet to be eligible for the jackpot.

2.    Use hot or cold coins: The temperature of your coin has nothing to do with wins or losses, and you’ll just end up looking ridiculous. What are you going to do, bring a blow-dryer to the casino? Keep your coins in the freezer before playing? Send a jolt of cold air into your computer’s USB port?

3.    Patterns can be predicted: There’s no way to tell which symbols are going to turn up on a modern slot. The RNG assures this with the precision of a computer.

4.    The zigzag system works: A betting system is supposed to be a method of play that allows you to beat a game on a consistent basis. Sold by con artists, these systems are inherently flawed. The zigzag system is sold online for actual money. This system encourages players to walk the casino floor looking for slots with winning symbols that are just slightly out of alignment. The idea is that the icons should align within a few more spins. This is not a thing. Don’t waste your time.

5.    Martingale also works: The Martingale system (another betting system) states that a player should always double their bet after a loss. When you eventually win, this is meant to cancel out all the losses you incurred along the way. When you’re playing slots, you can go broke if you use the Martingale system because of the RNG.

6.    Single coin bets: Some superstitious players believe that you’re more likely to win by betting a single coin. These are the same people who probably believe that black cats are bad luck. Some cats have black fur. Some have brown fur. Cats are only bad luck if you’re allergic to them. Anyway, the RNG determines the winning symbols on the reels and it doesn’t care how many coins you just pumped into the slot machine.

7.    A machine is due to hit: This is one of the biggest fallacies surrounding slot machine odds. Just because a machine hasn’t paid out in a while doesn’t mean the odds of you winning are going to change. For some reason, players become convinced that the next spin is going to make up for the dry spell. While slots are programmed to give back a certain percentage of winnings, this is calculated over a near infinite number of spins.

8.    Casinos can instantly adjust a slot: This paranoid belief centers around the idea that the casino can make a machine looser or tighter at will. While machines can be adjusted, this isn’t something that’s done on the spur of the moment to shut down a player on a hot streak.

9.    Slots pay in cycles: This myth claims that slots go through a cycle of payouts. Once that cycle has run its course, it starts over from the beginning. The idea, of course, is to observe the machine and memorize the pay cycle. The RNG makes this a ludicrous idea. 

10.    Playing free slots for fun will make you a better player: There is no proof that the more you play, the better you’ll be. 

Are there Different Types of Slot Machines?

The types of slot machines available at online and land-based casinos are more varied than most players would initially assume. That’s because gaming establishments are always searching for new ways to draw in customers, just the same way that a carmaker looks for new ways to improve their products. Why choose the standard model when you can choose the vehicle that parallel-parks itself? 

Keep in mind that a large number of slots fall into multiple categories, such as a multi-line slot that offers a bonus round and a progressive jackpot. If you prefer games that are more straightforward and less complicated, you can find slots like that too. That’s the wonderful thing about variety, as it provides those with differing tastes the opportunity to find the slot machine that’s perfect for them.

Reel Slots

Only found in land-based casinos, these were the original slot machines that used physical reels instead of video displays. No new versions of this type are produced and they are considered a collector’s item if you can get your hands on one.

Video Slots

The modern form of the slot machine, video slots use technology to display virtual reels. It’s not uncommon for these slots to include animation and clips from popular movies and TV shows. 

Straight Slots

The most basic version of the modern slot, this type of game awards prizes as determined by the pay table. In addition to normal wins, these games often feature scatter symbols, multipliers, wild symbols and even bonus rounds.


The most basic type, this machine offers a single payline across the reels. While this option can still be found, it’s becoming increasingly uncommon. Much of this is due to the fact that modern slots all feature virtual reels, so making 30 paylines doesn’t cost that much more than creating one.


Instead of a single line that pays from left to right, this popular option offers numerous paylines that stretch out in all manner of bizarre patterns on the reels. Just hitting one still results in a win, but it’s possible to win multiple times on a single spin. These have become the industry standard, and the 30-payline game is the most common. There are 50-payline games and even machines that pay right to left. 


When the reels have stopped spinning on this version of the game, the players may choose to spin again while holding one or more reels (usually those containing symbols with the largest payouts). Since the slot machine odds of getting a winning combination are increased with this option, the payouts are almost always set at a lower amount. 


While certain combinations of symbols offer a set amount, there’s also a top prize that can be obtained. This is known as the jackpot and it offers the largest of the game’s available payouts. This amount is often a fixed number, although the size of your wager can result in a potential increase.


Each time someone plays a progressive slot, a small percentage of their wager is allocated to the progressive jackpot. That means the prize continues to grow, and it doesn’t stop until the winning combination has been hit. Once that happens, the payout resets to a minimum amount and begins to build again. It’s not unusual to see a progressive jackpot offering a six-figure payout, and some may even climb into the millions.


Instead of just accepting a single denomination, this type of slot machine allows players to select how much they want to wager. This amount could be as low as a penny (remember pennies?) or it might climb as high as several hundred dollars.

Buy a Pay

This type of slot includes multiple payout tables. Higher wagers make you eligible for better payouts and the maximum amount must be risked in order to have a chance at the jackpot.

Bonus Round

If the necessary symbols appear on the reels, a bonus round is unlocked. In some cases, this is as simple as free spins with one or two of the reels displaying different icons. In other cases, the bonus round may unlock animated games that offer free spins or bonus amounts of money. In some cases, you have to unlock the bonus round in order to be eligible for a progressive jackpot.

Loose and Tight

These aren’t actual types of slots (and get your mind out of the gutter!), but players often use these terms to describe different games. A loose slot offers frequent payouts, while a tight slot is stingy when it comes to awarding money.

Leading Slot Machines

If you’ve ever played a slot machine, there’s a strong chance that one of the companies listed below was responsible for making it. Some of these companies power slots for online and in-person casinos while others focus solely on the internet market. 


These slots are designed and released by Betsoft Gaming Ltd., an online casino software developer based in London. Best known for their line of innovative 3D slots, this company is often cited as being on the cutting edge of the video slot industry. Learn More about Betsoft


Responsible for one of the largest online payouts in internet history, this virtual gaming manufacturer provides software for 32Red, Ladbrokes and numerous others.
Learn More about MicroGaming


NetEnt slots are created by Net Entertainment, a Scandinavia-based company that first made its name in the land-based casino business. While the online company was created in 1996, its actual roots within the gaming industry go back much further.
Learn More about NetEnt

RealTime Gaming

Founded in 1998 and including clients such as Bodog, this online casino company is known for its progressive slots, many of which are connected across all casinos powered by RTG.
Learn More about RTG


Rival slots, as well as other casino games from this online software provider, made their debut in April 2006. While the selection was limited to begin with, the company has since grown to offer over 160 games for both desktop and mobile gamblers.
Learn More about Rival

History of Slots

The term “slot machine” originally applied to a number of creations from 19th-century gambling devices to automatic vending machines. That all changed in 1898, when a Bavarian immigrant in San Francisco named Charles Fey created the first version of the modern-day slot. 

Known as the Card Bell, this machine included three mechanical reels, an automatic payout design and staggered stops. This version of the game included symbols taken from playing cards. The following year, Fey would replace these painted-on symbols with a more patriotic theme including stars and a depiction of the Liberty Bell. The game was renamed for the cracked American icon and getting three of these symbols across the reels would result in the top payout of 10 nickels. Once his invention was in working order, Fey started renting them to bars in exchange for 50 percent of the machine’s profits. Moreover, he was a prolific inventor during this period. In addition to the first real slot machine, he also created the first Draw Poker game. 

From 1958 until 2006, Fey’s grandchildren Marshall and Frank lived in Reno, Nevada and operated the Liberty Belle Saloon and Restaurant. Their grandfather’s inventions were on display in the building’s upstairs museum, along with numerous other vintage slots and pieces of casino history. Once the business closed, the Liberty Bell machines were relocated to the Nevada State Museum in Carson City. 

Increased Competition

Fey did a great deal of business with his slot machine innovation, and it was lucrative enough that multiple companies tried to buy the distribution or manufacturing rights. When Fey refused to sell, they were forced to look elsewhere.

In this case, “elsewhere” was Chicago, Illinois, the home of game manufacturer Herbert Stephen Mills. His company, the Mills Novelty Company, came up with a similar machine to the Liberty Bell and dubbed it the Operator Bell. It worked in much the same fashion, although it’s notable as being the first slot machine to include fruit symbols such as cherries and lemons.

An increasing number of Bell-like machines began to pop up in saloons across the United States. While the most desirable prize was money, some machines got around local laws against gambling by offering everything from cigars to free food.

What’s the Origin of Electronic Slots?

The potential for electronic games had been demonstrated as early as 1940, but it wasn’t until 1963 that Bally unveiled the first electronic slot machine. Known as Money Honey, this game featured an automatic payout up to 500 coins, as well as a bottomless hopper.

This type of game was immediately popular, and they soon began to replace their mechanical counterparts. Within a few decades, the classic lever on the side of the machines had largely been replaced by a series of front-mounted buttons.

Creation of Video Slots

In 1976, the slot machine industry took a major leap forward with the first video slot making its debut. Developed with the help of the Fortune Coin Company, this machine replaced physical reels in favor of virtual images of internal computer technology.

The game was initially tested in the Las Vegas Hilton and soon received approval from the Nevada State Gaming Commission. From there, it spread to other gaming destinations in the United States. Today, almost all slot machines in operation around the world fall into this category.

First Progressive Slot Machine

Progressive slots offer the opportunity for huge wins, as a percentage of each wager is added to an ever-expanding jackpot. The first game of this type was known as Megabucks, and it debuted in 1986 after being created by International Game Technology (IGT). 

Slot Machines and the Internet Age

Playing free slots for fun wouldn’t be possible without Microgaming Software. In 1994, it became the first developer to create an online casino. This virtual milestone opened the floodgates for the market, and it wasn’t long before companies such as Cryptologic, IGT, Playtech and Betsoft were also getting in on the action.

While the earliest online slots had crude sound effects and graphics, they made major strides in the following decades. This led to the creation of i-Slots, the next-generation machines that feature superior audio and state-of-the-art animation. In another few years, we might even have holographic slots. Who knows?