Three Reel Slot

Slot machine that has the traditional 3 spinning reels to randomize the slots symbols.

Return to the slot machine terms main page.

Three-reel slots were the first slot machines invented. Charles Fey, a machinist living in San Francisco in the 1890's, invented the first slot machine, the Liberty Bell. The Liberty Bell slot machine used a 3-reel mechanism to randomize the reel symbols. This design became the conventional design for slot machines for decades to come, so that there is a whole type of slot machines these days known as Classic 3-Reels.

Tradition wasn't the only reason slot machines had three reels. There were mechanical concerns, as well. For the slot machines to be affordable enough and small enough to fit in casinos, the 3-reel design remained the standard. The reels had to be a certain size to fit in the slot machine box, so the number of reel symbols were limited. The same could be said for the number of reels.

Attempts were made to increase the number and size of reels. The Big Bertha slot machine increased the size and number of reels, while the Super Big Bertha expanded to 8 reels. These machines cost around $150,000 to produce, and they continue to be remembered as monstrosities inside the casinos of yesteryear. 5-Reel and 7-Reel machines were also marketed.

With the random number generator added to slot machines, new possibilities opened up to slots designers. Electronic slot machines do not have the same size restrictions that mechanical slot machines once did, so that 5-reel slot machines became quite popular in their own right. Many of these 5-reels were video slots or offered progressive jackpots.

Meanwhile, three-reel slots continue to be some of the most-loved slot machines on the market. Players love the classic three-reel slot machines, despite having their own electronic RNGs. Even online slots casinos offer video slots (5 reels) and classic 3-reels, which copy the most popular three-reel slots in gambling history.