The Lowdown on Slot Machines: How Do They Work?  

Slot machines are little more than the computer chips they run on.

Unlike slot machines from decades ago, today’s slot machines operate by computer, with computer chips that are programmed to select numbers randomly. When you pull the handle or hit the spin button, the computer’s random number generator pulls three numbers from its bank.

The numbers the computer selects are matched to symbols displayed on the slot machine’s screen. Most numbers match symbols that don’t offer a payoff or a big payoff. Fewer numbers match symbols with big payoffs.

Slot machines may look like the spinning reels take a few moments to land on the correct symbol, but those moments are largely for show. In reality, the computer has chosen the three numbers the instant the player hits the button.

The computer chips that govern the random number generator are programmed to pay out at a particular, legal rate. For example, one state might require a minimum payout of 85 percent. A casino can order slot machines to pay out at any rate above that percentage. Most will beat that percentage by many points, and the payout percentage will often be greater for greater denominations of coins played. If you play a nickel machine, for instance, the machine’s payout rate might be 93 percent, where a quarter machine’s payout rate might be 94.6 percent. The chip controlling the payout rate can be changed, but casinos are required to report any such changes to their state’s Gaming Commission.

The most important thing to understand about slot machines, however, is the fact that each spin is independent of other spins. That is, continuing to play on one machine won’t put you closer to a win than hitting the spin button only once. Because of the random number generator, winning on a slot machine is a matter of pure luck.