It’s an online slot with an additional jackpot feature, which punters can play via the casino’s website. It comprises all the regular slot features and a progressive pot that increases with every player’s bet. The type of jackpot slots and their pots’ fallout values can vary immensely. They can be simple 3-reel slots with no extra features, complex games with unique structures and advanced mechanics, and everything in between.
The size of the pot and its target value is determined by the software supplier, and it can be as low as a few hundred and as high as millions.

Two words – simultaneous access.

While just one person can play a regular, physical slot machine at any given time, an online slot has no limit of players that can access it.

In land-based casinos, there are often “networks” of slots sharing the same jackpot, which makes the grand progressive prize grow a little faster. They can contain from a few to a couple of dozen slots. However, in the end, they are always limited by the physical space of the casino.

Online jackpot slots can be played by thousands of players at the same time, which makes the pool grow much more rapidly. At the same time, it allows the software supplier (a company that produced the game) to lower the contribution percentage, therefore keeping the base game RTP (return to player) on an attractive level.

Jackpot contribution is a fraction of a bet that seeds the main pot (and side pots, if there are any). It’s usually expressed as a percentage. For example: if a jackpot contribution is 3% and your total stake per spin is €1, 3 cents from each spin go to the pot. This is, of course, a very simplified example, as software suppliers develop numerous different mechanics to implement jackpots in slots. Some may have a fixed amount of contribution regardless of the bet size. Others may increase the contribution along with the stake value. However, in the majority of slots, it’s a simple fixed percentage. It’s best to check the slot’s rules page or info page to determine what type of contribution you’re dealing with.

We already mentioned that online jackpot slots are superior to physical ones because they can maintain an attractive RTP level due to the volume of simultaneous players. What do we mean by that? First, we encourage you to read our article explaining how RTP works. This knowledge will undoubtedly help in understanding jackpots.

Even though the total RTP may be very similar between progressive jackpot slots and “normal” ones, we mustn’t forget about the contribution, as mentioned earlier. If a standard, non-jackpot slot has an RTP of 97%, that will be its total and effective average value. In a jackpot slot, a description like “97% with jackpot contribution of 3%” means that its effective average RTP value is 94%. What does it mean to you as a player?

That you can expect a little bit less average return from the slot because part of your bets has to charge the progressive jackpot.

Is it a noticeable difference? Not really. As you’ll read in our article about RTP, that value is calculated based on millions of spins. Therefore considering an average playing session consisting of a few hundred or even thousands of spins, it’s impossible to spot. Suppose you play just one jackpot slot all year long, for a couple of hours every day. Then if you calculate your entire history, those few percent might matter.

To answer the main question of this paragraph: yes, it’s worth playing online jackpot slots, but as long as the contribution doesn’t lower the base RTP too much and the total RTP is still on an acceptable level.

There’s champagne, of course.

In all seriousness, though, we mean the next jackpot cycle. Does it start from zero? And if not, where did the starting amount come from? Logically, no jackpot begins from zero because who would play it then? Or who would stake their money to hit a 100 EUR jackpot when the last win was €200,000? Again we need to come back to the contributions. The percentage of each bet we’ve mentioned before is not only seeding the currently active pot, but its small fraction is also being “put aside” to guarantee an attractive starting point for the next cycle.
“But who supplies the funds for the first jackpot cycle when the slot is released”? – you may ask. That usually comes down to the deal between suppliers and casinos. It can be either of them or a simple split between the two depending on the cooperation.

The biggest, most attractive, and most played jackpot slots are the network ones. Meaning the pot you’re playing for is shared between many online casinos that are part of the slot supplier’s network.
Quick example: Microgaming (supplier) offers the Mega Moolah slot, which has a network jackpot. Customers of every casino that offers the Mega Moolah slot contribute to one pot that can be won on any of those websites. So regardless of which casino you play at, the jackpot amount will always be the same everywhere.

As you may expect from the name itself, local jackpots come with a pot fueled only by customers from the casino where they’re offered. Naturally, they will reach lower amounts than the network ones since the number of players contributing to the pool is considerably lower.

This is a brilliant jackpot model first introduced by Red Tiger Gaming company. It’s shared between most of this supplier’s slots and can be either network or global (depending on the casino management’s choice).

There are two main formats.

The first one is time-limited. The two most popular options are daily and hourly. Jackpots must fall either before midnight or before a whole hour has passed. Because of that, the prizes won’t be as valuable as in the long-term pots, but a guaranteed winner every hour or every day is also a strong selling point.
The second format is value-limited. The pot now comes with a cap, say 1,000 EUR, and the jackpot must drop before reaching that amount.
The great thing is that all those variants may run simultaneously, so there is always something attractive to fight for.

Often yes, but not always.

Some jackpot slots state that playing with higher stakes increases the chance of hitting the jackpot. However, suppliers never put it in a numerical form, so in the end, you never know if the increased chance is proportional to the increased value of your bet. We’ve seen numerous high-value jackpots hit with minimum or close to the minimum bet, so real-life examples prove it’s possible. Always refer to the slot’s rules page to ensure the value of your bet is crucial in calculating the chance of winning the jackpot.

In this article, we’re mainly talking about progressive jackpots. However, if you’re a regular online casino player, sooner or later, you’ll come across so-called “fixed” jackpots. To be honest, we don’t consider them to be actual jackpots. Nobody contributes to their value, so it’s difficult even to call it a “pot”. It will usually be a fixed amount that constitutes a specific multiplier of your total bet, so you will see it changing when you change the stake, but it won’t change along with your spins. We treat them instead as regular big wins, just presented as a specific amount and placed somewhere outside the reel area to accent its significance.

One of the popular slots boasting such a feature is Wolf Gold by Pragmatic Play.

It’s a question without a straight answer unless you’re satisfied with “it depends”. The big, long-term jackpots do not have a specific date or time, which indicates their fallout. They usually have a certain threshold, which, when crossed, will mark the pot as “hot”. Hot jackpots are much more likely to drop. However, winning them before they reach that moment is not uncommon either.
With “must fall” jackpots, the situation is a bit clearer because they either fall close to the end of their time frame or their pot limit. In general, there is no way of predicting when exactly a jackpot will drop.

The online gambling industry seldom explodes with the news of a record-breaking jackpot amount. Even with network pools, it takes a significant amount of time to accumulate an amount that will make it to the worldwide news. Nevertheless, it has happened a few times over the last decade.

Here are the 10 biggest jackpot hits in online slots:

• €19,430,723 (€15 bet) – April 2021 – Absolootly Mad Mega Moolah – Belgium – Napoleon Sports & Casino
• €18,915,872 (€0.75 bet) – September 2018 – Mega Moolah – Anonymous – Grand Mondial Casino
• €17,886,199 (£0.25 bet) – October 2015 – Mega Moolah – UK – Betway
• €17,860,868 (€0.25 bet) – January 2013 – Mega Fortune – Finland – PAF Casino
• €17,529,047 (£0.80 bet) – April 2021 – Book of Atem WoWPot – UK – 32red
• €14,272,856 (stake unknown) – August 2020 – Mega Moolah – Sweden – Lucky Casino
• €13,328,028 (stake unknown) – January 2019 – Mega Moolah – Canada – Zodiac Casino
• €11,418,728 (stake unknown) – March 2019 – Mega Moolah – Luxury Casino
• €11,736,228 (€0.50 stake) – September 2011 – Mega Fortune – Norway – Betsson
• €7,595,435 (€50 stake) – July 2021 – Hall of Gods – Finland – Casumo

If you had at least a glance at the list above, it’s easy to spot that one name appearing way more often than others.

Microgaming’s first network jackpot launched back in 2006 on an African-themed slot under the same title. It offers a 4-tiered progressive pool – mini, minor, major, and mega. Mega Moolah currently holds the Guinness World Record for the “Largest jackpot payout in an online slot machine game“, and looking at the history of all online jackpots, it will be a tough one to break.

Currently, 10 games share the Mega Moolah pool:

• Mega Moolah
• Atlantean Treasures
• Absolootly Mad
• Fortunium Gold
• Immortal Romance
• Juicy Joker
• Mega Moolah Goddess
• The Witch’s Moon
• Lucky Bells
• Starlite Fruits
• Thunderstruck II

Triggering the Jackpot Wheel in Mega Moolah happens randomly, without any additional prerequisites. Regardless of the stake, any spin can open up a chance to hit the Mega jackpot.

NetEnt’s most popular progressive jackpot slot launched 2 years after Mega Moolah, in 2008, and has also created quite a few millionaires during its lifetime. The game itself boasts a luxurious theme filled with extravagant jewelry, expensive drinks, and fancy cars. To stand a chance of winning the biggest jackpot, players need to trigger the Bonus Wheel by scoring three Bonus symbols on reels 3, 4, and 5. The wheel consists of 3 rings, each filled with values, jackpots, and arrows. Landing on a value awards the corresponding amount of coins and ends the feature. Landing on an arrow advances to the next inner wheel. The corresponding pool is paid out when the selector arrow aligns with the jackpot name.

First released in 2020 on a Wheel of Wishes slot, it is another impressive child of the Microgaming software provider. Short history hasn’t prevented it from securing one of the top spots for the biggest jackpot hit in an online slot. Just a year after the first launch, WoWPot burst with a €17.5 million jackpot on the Book of Atem slot.

The number of games offering this attractive pool grows continuously and currently contains the following titles:

• Wheel of Wishes
• Book of Atem
• Ancient Fortunes: Poseidon Megaways
• Sisters of Oz
• Cash ‘N Riches Megaways
• Queen of Alexandria
• Sherlock & Moriarty
• 9 Blazing Diamonds

In 2010 four Norse gods descended from Asgard into the realms of men to grant them a chance to win a life-changing jackpot in this slot machine by NetEnt. Hall of Gods comes with a cartoony Scandinavian theme featuring recognizable characters from Northern mythology – Odin, Thor, Loki, and Idun. On top of a slot with Expanding Wilds and Free Spins, it is also one of the most popular progressives that has proven its worth by awarding many multimillion jackpots, with the highest being €7.5 million.

Players must score three Bonus symbols in the main game to face a chance of landing one. Having done so, they stand in front of a shield wall. Striking individual shields reveals either coin values or jackpot names. Matching 3 identical results awards the corresponding prize.

It’s one of the very first network jackpots in the online gambling industry, dating back to 2005. It didn’t manage to gain such popularity as NetEnt’s later progressives – Mega Fortune or Hall of Gods; however, it still marked its place in history with a top jackpot paying out a sizzling €3,332,981.

It’s important to note that Arabian Nights can be either a local or a global jackpot, depending on the operator’s preferences. If you’re hunting the biggest potential prize, make sure you’re playing with a casino that has joined the network.

Six years after the Mega Fortune release, NetEnt decided to follow up on the success of their most popular progressive and delivered another slot bursting with extravagance and luxury. Initially available only to a small group of top-tier operators, it used to gain value a lot slower than its predecessor. Currently, Mega Fortune Dreams is present in most online casino lobbies, and its jackpot pool is growing more rapidly. The two biggest hits recorded to date are €5,050,845 and €5,050,957. Apart from these, Mega Fortune Dreams literally made dreams come true for many players, delivering nearly 30 top wins ranging between €1.5M and €5M.

Yggdrasil joined the progressive jackpot game in 2015 with their Joker Millions slot. Not long after, in 2016, they released another machine that shared the same pool – Empire Fortune.

Joker Millions comes with a sticky respin feature triggered by landing at least one jackpot symbol on each reel. Filling up the entire screen with jackpot symbols awards the top prize.

Empire Fortune takes a slightly more classic approach. The jackpot feature is in the form of a wheel with different values and arrows. Like in Mega Fortune, landing on an arrow advances to the inner wheel, and the top prize is only available on the third, central wheel.

The largest hit on this jackpot happened in 2018 when a Swedish player betting merely 5 SEK (about €0.50) scooped the main prize of €7.8M.

Red Tiger entered the online casino scene in 2016 with their unique approach to jackpot functionality. Instead of teasing players with massive, life-changing amounts, they focused on fallout frequency. The principle was simple: Daily Jackpots must have dropped before a specific time within a 24-hour window, while Ceiling Jackpots had a max value cap. Those jackpots were local, meaning that each operator’s players contributed to them separately. Therefore the amounts for Daily Jackpots depended on the size of the customer base. Later on, Red Tiger also adapted the pooled network model and allowed operators to share the biggest jackpots, which started reaching much higher values. However, they have yet to reach the multimillion levels that could compete with the likes of Mega Moolah and Mega Fortune.