Understanding Different Types of Slots & How They Work

The first slot machine in its ‘modern’ version was invented in 1894 by Bavarian-born American inventor Charles August Fey. It was a coin-operated gambling machine that Fey, a San Francisco mechanic, built in his basement. Fast forward to 1976, when the first video slot machine was introduced, featuring an electronic color display and logic boards. The Internet revolution of the 1990s saw the first online casino with online slots launched in 1994. Since then, slots can be found at top mobile casinos providing players with access to thousands of slots at their fingertips from any smartphone or tablet device.

But despite leaps in technology that revolutionized the way we play slots, many basic principles of slot machines remain similar.

How Slots Work

The first step to learning how to win slots is understanding the principles of the game. Whether digital or mechanical, a slot machine will contain reels with symbols that represent different values. One or more paylines will outline the pattern of symbols that needs to align on the reels in order to generate a win.

The player will spin the slot’s reels by pulling a lever or pressing a button (for mechanical and computerized slots, respectively) with the aim of landing a winning combination of symbols that corresponds with the slot’s paylines. The payout will depend on symbol values, and the amount of money wagered on the payline.

It is important to know that all slots have a Random Number Generator (RNG) which makes sure that the outcome of every spin is completely random.

Types of Slots

Beyond basic similarities, slots differ significantly in their number of reels and paylines, features, payouts, bonus rounds and more. To make the most out of your slot experience, you need to find a slot that suits your gameplay, personality, and strategy.

Below are the main types of slot machines available to players:

  • Classic Slots: These are the simplest type of slot games, featuring 3 reels and usually one payline. The symbols are typically fruits, bars, and lucky 7s. Classic slots don't usually have bonus features or free spins, but they can offer large payouts for landing a specific combination of symbols.
  • Video Slots: These are the most common type of slot games found in online casinos, featuring 5 reels and multiple paylines. Video slots often have more complex themes and graphics than classic slots, and they usually have bonus features such as free spins, multipliers, and mini-games.
  • Progressive Slots: These are slot games where a small portion of each bet made by players contributes to a large jackpot that continues to grow until someone hits the winning combination. These jackpots can reach millions of dollars and are often linked across multiple casinos.
  • 3D Slots: These are video slots that use 3D graphics to create a more immersive gaming experience. They often have elaborate animations and cinematic cutscenes, and they may also feature interactive bonus games.
  • Branded Slots: These are slot games that are themed after popular movies, TV shows, or celebrities. They often feature recognizable characters and settings, and they may include bonus games that are tied to the theme of the brand.
  • Megaways Slots: These are video slots that use the Megaways mechanic, which allows for a variable number of symbols to appear on each reel. This means that each spin can have a different number of paylines, often up to tens of thousands. Megaways slots often have cascading reels, which means that winning combinations are removed from the reels and replaced by new symbols, potentially leading to multiple consecutive wins.
  • Cluster Pays Slots: These are video slots where winning combinations are created by landing a cluster of matching symbols rather than lining them up on a payline. Cluster pays slots often have unique reel layouts and may include features such as cascading reels and sticky symbols.

Nowadays, it is common to find slots that combine many of the features above. For example, a multi-payline slot that has 5 reels and offers mega spins and multipliers, etc.

Playing Progressive Jackpot Slots

Progressive slots offer a community prize pool. The casino operator or game developer will usually put up a prize seed which is a set amount of money that goes into the prize pool. Then, a portion of every qualified wager made on the progressive slot by any player will be allocated to the jackpot prize pool. The prize will keep growing until a winning combination is triggered by a lucky player who will win the jackpot. Once won, the prize pool will reset and the jackpot will start building up again.

Progressive Jackpot Tiers

While some progressive slots make any size wager eligible for winning the jackpot, many offer several betting tiers. So only players that placed wagers over a certain amount will qualify to win jackpots. To avoid disappointment, always check the required bets to qualify for jackpot winnings and select the bet level to match the prize you wish to play for.

Jackpot Record Prizes

Although the odds of winning a jackpot are slimmer, rewards are much larger. For example, in 2015, a jackpot of $13.2 million was won on Mega Moolah – a 5-reel, 25-payline progressive slot developed by Microgaming. It has set a Guinness World Record for the largest online jackpot ever won and has since been surpassed with even bigger wins.

Local vs Network Jackpots

Most casinos feature progressive jackpot slots. On network progressives, contributions from wagers from all the participating casinos will count towards one common prize pool. This leads to prizes that can grow very quickly to jackpots worth many millions.

There are also progressive slots with local jackpots that are shared amongst players of a specific casino. Although local jackpots tend to be smaller, they usually provide better odds for winning, providing a good incentive for fans of the best real cash slots.