The Technology – and Math – Behind Online Progressive Jackpot

By Tim Jones 

May 14th, 2026

BURLINGTON, ON

If you’ve ever been to a Las Vegas casino or, indeed, any large casino resort, you’ll probably have noticed the jackpot tickers above the machines, notably slot machines.

They’ll show massive prizes, sometimes worth millions of dollars. It is quite alluring, and it’s conceivable that it attracts a lot of people to casinos, hoping for that lucky spin.

Do you know how these prizes are won?

The same experience occurs with online progressive jackpot slots, though there are certain differences. The main similarity, though, is that the headline prizes can be just as big, reaching several million dollars with some games. But do you know how these prizes are won? It’s actually quite simple, but it’s interesting when you break down the mechanics.

A prize funded by players

To start with, let’s explain what a progressive jackpot is. Every game technically has a jackpot, i.e., a top prize, but progressive jackpots are somewhat different. It is, in effect, a prize funded by players. Usually, it starts with a seed amount provided by the casino, let’s say $100K, and then a small amount is taken from each wager – small enough that you won’t notice, like 1 cent for every dollar – and that grows the jackpot.

As you can gather, it takes a lot of playing to grow the jackpot to several million. For instance, let’s say that the average wager was $1 and the jackpot contribution was 1%, then it would take 100 million spins to add a million to the prize, or a billion spins to add 10 million. There is an economies-of-scale principle applied by casinos, so people will be playing the same game, growing the jackpot across different casinos. Sometimes multiple games are connected to a jackpot network, allowing the prize to grow more quickly.

Everyone wants to see this show up on the screen. It does happen.

So, how is the prize won? It’s not based on a specific set of results, nor some combination of symbols. It’s random. The developer behind the game will use a random number generator to decide the exact amount that will be paid as the jackpot. For example, it might be $3,743,164.54. Nobody will know that figure – not even the casino operators.

The tipping point

Can you guess how it is awarded? Well, the player whose jackpot contribution tips the balance by reaching the previously determined amount will be awarded the jackpot. For instance, if we use the figure above: imagine that the jackpot currently stood at $3,743,164.53, and your $1 bet added the final penny to the jackpot; you would be awarded the prize. As we said, it’s quite simple.

Winning is a thrill!

The attraction of these games is that they are random. However, there are a couple of caveats. For a start, bigger bets are more likely to win. Why? Well, if you are betting $100 per spin, you are more likely to be the person who tips the balance with the jackpot contribution than the person playing for 20 cents. Secondly, some games, but certainly not all, will have minimum bet requirements to be eligible for the progressive jackpot. But everyone usually has a chance.

As you might expect, a mini internet ecosystem has grown up around online progressive jackpots, with websites tracking the prizes and discussing tactics. It is sometimes worthwhile checking these platforms to see where to find the biggest prizes, but it’s worth bearing in mind that it is impossible to tell when and where the massive prize will be delivered.