Types of Slots

A comprehensive list of the different types of online slots including different RTP, variances, gameplay, bonus symbols, paylines, and even reels.

Slots come in a wide variety of flavors. From three-reel slots to online 3D slots, there are many that appeal to different kinds of gamblers.

In this article, we break down all types of slot machines you will find on online and land-based casinos to help you play on the few that truly pique your interest.

By Reels

The most straightforward slot category that everyone understands is reel-based slot types. Reels are the vertical wheels where symbols spin around. Standard slots come in three to five reels while other games use six or more reels as their main feature.

Mechanical slot machines were obviously manually built so fewer reels made sense, but now online video slots are taking over, screens can accommodate many more of these.

Three-Reel Slots

When people think of slots, the first thing that pops into most people’s heads is three-reelers. Simplicity is the flavor these slots are attempting to achieve by invoking the vintage slots that appeared in the first Las Vegas casinos.

Renowned software providers look for ways to make three-reel slots interesting by adding various features. One example is NetEnt‘s Mega Joker that includes a “Supermeter” mode.

Five-Reel Slots

You may notice how the majority of slots in any casino consists of ones with five-reels or 3×5 reels. There is a rich variety of five-reel slots with ones that offer straightforward gameplay and strategy. Other slots include dazzling payout features such as multipliers, jackpots, and bonus games.

A notable pioneer of the industry with more than 800 online games with a rich selection of five-reel slots is Microgaming software. ThunderStruck is one of the software provider’s long-running five-reel slot games.

ThunderStruck II by MicroGaming
ThunderStruck II by MicroGaming

Six-Reel Slots

Adding more reels to a slot comes down to having more pay lines than traditional five-reel slots. In the case of six-reel slots, many of its iterations offer more than 100 pay lines to match symbols in 4×6 or 3×6 reels.

Zeus III is one of the popular six-reel slots from WMS, which has 192 pay lines and Zeus Wilds feature.

Seven-Reel Slots

Lucky seven-reel slots goes a step further from other slots with two additional reels. What makes these slots appealing to gamers is the number of symbols lining up during each spin. Seven-reel slots RNG is still the same as five-reel slots with the additional reels acting as eye-candy to any player.

WGS Technology‘s Farming Future is a solid example of seven-reel slots with 3×7 reels.

Ten-Reel Slots

When you want the whole screen to fill with massive amounts of symbols, you can never go wrong with ten-reel slots. Many ten-reel slots break away from the traditional 3×5 feels by having two different sets of reels.

In the case of Forest Mania from iSoftBet, the game has a 4×5 and 12×5 reels. Having numerous symbols line up with the ten-reel slot’s pay line can be a visual treat to any player.

Forest Mania by iSoftBet
Forest Mania by iSoftBet

By Paylines

Paylines are where players need to lineup a slot’s symbols to determine their payout. Slots tend to make the number of paylines an attractive feature to any punter, including ones that provide anyone with many payout opportunities.

Single-Payline Slots

Vintage slot machines usually have only one pay line, which is a straight line running across the reels. Three-reel slots tend to have only one pay line to achieve the classic slot gameplay.

What makes single-payline slots appealing is how players do not need to increase their bets just to maximize their chances of winning in each spin. One example of a slot that brings out the best of the game with only a single-payline is Joker Cash from Bingo Entertainment.

Multi-Payline Slots

Plenty of modern and upcoming slots have more than one paylines that give players plenty of opportunities to win.  Even popular three-reel slots use three to nine paylines. Take note that most multi-payline slots require additional bets to turn on two or more paylines.

Book of Ra from Novomatic is a solid example of ten-payline slots that require additional bets to activate more than one line.

100-Payline Slots

When just a few paylines are not enough, 100-payline slots are just what the doctor ordered. Players flock to these slots because of the sheer amount of lines to match the symbols. 100-paylines also make wild symbols exciting since the feature allows players to maximize most or all of the lines.

Endrophina has a solid 100-payline slot called Chance Machine 100 that features scatter and wild symbols.

100 Paylines of Chance Machine 100 by Endorphina
Paytable of Chance Machine 100 by Endorphina

By Features

Wild symbols, scatters, bonus games, and other features are what make many slots enjoyable. There is nothing like seeing multipliers increasing your payouts or entering a free-spin mode.

Wild Slots

Wild symbols are popular features involving a special symbol that substitutes others when lined up on the payline. Multi-payline slots go well with wild slots since the feature opens the door to massive payouts.

Certain software providers expand on the wild symbol features by using a wild reel feature instead. Jurassic Park from Microgaming is one example where a reel is full of wild symbols that complete any payline.

Multiplier Slots

As the name suggests, multiplier slots have a feature that doubles, triples, quadruples, or multiplies the payout of any win per spin. Slots with this feature tend to have bonus spins that contain different multipliers.

One of the slots that take Multiplier to god-like levels is Rise of Olympus from Play’n GO. Players can grow the multiplier up to 20x when the free spins are active.  

Scatter Slots

Scatter features in slots have different functions across various games. Certain scatter symbols give players a random cash prize while others act as multipliers when symbols are matched on a payline while a scatter is present.

Various slots also use scatter symbols as a free spins activator such as Miss Kitty from Aristocrat. Players can activate the scatter feature when three moons appear on the first three reels.

Free-Spin Slots

Everything is better with free money, including ones from slot games. Free-spin features allow players to spin the reels a set number of times without staking their bankroll. Your last bet before the feature is triggered will determine the bet amount in each free spins.

Iconic casino games made free-spins an attraction to their slot such as Wolf Gold from Pragmatic Play. When you trigger the feature, a Wild Wolf Reel can fill up the middle three reels during the free spins round.

Nudge Slots

Punters have experienced numerous spins where one or more symbols were just a step away from the payline and just want to find a way to give the reels a slight push. Nudge slots complete that wish by moving the reels to a position where the symbols line-up with the paylines.

Popular nudge slots include Hot Nudge from NoLimit City, which features a wild reel that can nudge upwards to cover the entire vertical reel.  

Reels Hold Slots

Imagine symbols that stay put throughout succeeding spins, giving you better chances at matching more of them in the next spin. Such a feature exists as sticky symbols where players receive a free re-spin while symbols stay put and others spin away.

Yggdrasil‘s Joker Millions is a solid example of reels hold slots with a sticky symbol feature in the form of the Jackpot Spin and Freeze & Respin bonus functions.

Cascading Slots

A cascading slot, or free-fall slot, is a game in which when a combination of winning symbols occurs, the very same symbols are removed to leave room for new ones to cascade down. These tumbling reels slots offer somewhat of an automatic free re-spin feature and allow players to have a more exciting time gambling.

Gonzo’s Quest, by NetEnt, is the most popular online cascading slot game to date. It has an RTP of 95%, along with medium volatility. It is made up of a 5×3 grid and 20 paylines.

Pick’em Bonus Slots

Giving players choices make any slot games more exciting, which is the thought used for pick-em bonus slots. Certain slot bonus games have you playing a shell game where you pick a symbol or picture that contains random prizes such as free spins or instant cash payouts.

You can try your shell-game luck through Betsoft‘s Whospunit. During the bonus game, you select the suspect and interrogate them. Finding the right culprit leads to a massive payout.

Slot Symbols (examples)
Slot Symbols – Wild, Scatter, Bonus & Standard Slot Icons

By Jackpot

Slot jackpots also come in different flavors such as the low-risk ones with fixed rates. While the odds of jackpots vary in each category, the ones with the lowest chances of winning tend to have a life-changing payout.

Jackpot Slots

Common jackpots usually have a fixed cash prize where the prize amount remains the same and is not affected by the bet amount. While the payout rate is smaller than other jackpots on the list, you have a good chance of winning fixed jackpots.

NetEnt‘s Gold Rush has a good example of a fixed jackpot in terms of the highest possible payout. Players can win the jackpot prize when they set the bet to the max amount and matched three Gold symbols.

Progressive Jackpot Slots

Nothing is more exciting than the growing jackpots among progressive slots. Payout rates among these slots grow each time a player spins the reels. It is important to note that every progressive jackpot slots refer to local machines

Slots with localized or standalone jackpot include Dancing Tiger from Novomatic. Dancing Tiger features six different jackpots with the Grand and Major ones that keep growing with each spin.

Wide Area Progressive Jackpot Slots

Players can expect to be on the news when they win the highest payout rate of any wide-area progressive jackpot slots. These slots take progressive jackpots a step further by allowing multiple players across many machines and online games to contribute to the payout rate. Jackpots from these machines can reach millions of dollars in prizes.

One of the popular wide-area progressive jackpot slots is Mega Moolah from Microgaming, which awarded Jon Heywood $13 million.

Mega Moolah by Microgaming
Mega Moolah by Microgaming

By RTP

Return to player (RTP) determines the house edge or your chances of winning back your money as well as acquiring a profit. Slots have varying rates of RTP where certain games have consistent payouts that let you play longer while others have a higher house edge compensated with better payouts.

High-RTP Slots

Loose slots are a term for high-RTP slots with a 98% and above edge for players. With a house edge of 2% or lower, you have a good chance of a small profit out of your initial bets over a long period or through numerous spins.

Many software providers make use of high-RTP as a feature of their game such as Playtech‘s Ugga Bugga, which has an RTP of 99%.

Medium-RTP Slots

Plenty of slots offer a slightly better house edge than other games with an RTP of 95% to 97.99%. Medium-RTP slots provide a reasonable advantage to the players where you have better odds at doubling your bets with many spins.

Players can get a balanced edge with slots like Cleopatra from IGT. With an Egyptian theme, Cleopatra offers around 95% RTP.

Low-RTP Slots

Casinos tend to have the edge with low-RTP slots that have an RTP range of 94.99% and below. With RTP that can go down to 80%, low-RTP slots are all about high-risks with high-rewards. For other low-RTP games, it is all about providing a mixture of gambling and entertainment.

Slots that provide the house with a better edge is Buffalo from Aristocrat with an RTP of 94%. Despite the low RTP, Buffalo boasts 1024 pay lines with multiplier and “Xtra Reel Power” features.

how to calculate RTP in slots
Wondering how to calculate RTP in slots? Just subtract the house edge!

By Volatility

Slot volatility, or variance, determines the number of wins vs losses. Certain slots give the highest possible payouts with fewer chances of winning while others allow players to consistently win smaller margins on their bets.

High-Variance Slots

High-risk comes with high-variance slots where payouts are less frequent than other games. Despite the risk, high-variance slots usually have the highest payout rates when you get a win.

Examples of high-variance slots include Montezuma from WMS, which has a free spin mode with a combination of multipliers. You can achieve incredible profits from the game when you get a maximum of 25 free spins and a max 10 multiplier during the bonus section.

Medium-Variance Slots

Games that offer a fair odds of doubling your initial bets are medium-variance slots. Payouts occur frequently through medium-volatility games with winnings that can reach two to three times your bet. Given the chances and winning potential, medium-variance slots are recommended for first-time players who want an authentic taste of online gambling.

NetEnt’s Twin Spin is a good example of a medium-variance slot that offers 243 ways to win and other high payout features.

Low-Variance Slots

At the other end of the spectrum are low-variance slots that allow players to enjoy frequent payouts with a tidy profit. With favorable odds to a player, low-variance slots offer consistent wins and marginal profits.

Bomber Girls from Microgaming is a low-variance slot with many ways to win such as the wild symbols that can double the payout of any symbols it substitutes.

slots variance
Volatility (also called variance) is a measure of how often a slot is likely to hit a winning combination and consequently, its average payout size.

By Gameplay

Certain software providers not only give players a fun and exciting way to double their money, but they also create an unforgettable experience in each spin.

3D Slots

One method of making slots exciting is to switch all flat icons, reels, and background screen into 3D rendered images and symbols. 3D slots are all about the visual flair that gives you lots of eye candy in each massive win.

No other software provider has made a name for itself in the 3D slots category other than Betsoft. With titles such as Gears of Time and Spinfinity Man, Betsoft can achieve Hollywood-like 3D animations and visual effects.

i-Slots

Immersing players to a developing story in each spin is the defining feature of i-slots (or, “interactive slots”). When players complete specific requirements such as matching high-paying symbols, they are treated to an interactive story where they have control over what happens next.

Rival is one of the notable software providers that focuses on i-slots. In their Spy Game slot, for example, players take on the role of an agent to bring down a weapons factory by spinning the reels.

Cluster Pays Slots

When you combine slots and puzzle games, you get cluster pay slots. Cluster pays slots do not have a payline. Instead, players create a match from similar symbols touching each other. Every matched symbol creates a space for more icons to fill the space, allowing for more payouts if the new symbols create a match.

Golden Glyph from Quickspin is one of the notable clusters pays slots with interesting features. One of these features is the “Power Wild” which leaves behind one of four power-ups each time you make a match.

Aloha Cluster Pays by NetEnt
Aloha Cluster Pays by NetEnt

Numerous slots across various casinos cater to everyone’s preference. By going through the different types of slots, you can easily narrow down your search for your preferred slot games that are worth your money.