Progressive slots are slot machines that accumulate towards yet another jackpot over and above any amount that you may actually win on the machine. A small portion of each player's bets go towards this jackpot. Hundreds of online slot online gambling sites offer the exact same progressive slots, as well as the progressive slot wager portions from all of these sites are centrally pooled to make up the grand jackpot, which may be won by playing at any of these sites. At land-based casinos the exact same principal applies, the real difference being that a range of physical slot machines are linked together to form a progressive slot machine network, paying out a progressive slot jackpot beyond the payouts that each machine makes to players on their own.

There are 3 types of progressive slot machines in real-world casinos.