# How Slot Machines Work

By Naomi Rufian

Topic: Machines

[Open the interactive Jig](https://ask.jig.com/j/Qp7Vi5Wonl0T)

## Guide

### 1. A machine of chance

A slot machine is a game of pure chance\. You pay, start a spin, and three reels decide whether a few coins come back\. Let’s open one up and see what really picks the result\.

Drag the background to turn the machine\. Use the arrows to move through the steps\.

### 2. Coins become credits

A coin drops through the slot\. Inside, a coin checker tests its size and weight, then the credit meter counts it\. Modern machines take paper notes or tickets the same way\.

### 3. Pull the lever

The lever only starts the spin\. The reels whirl, then stop one after another, left to right\. The pause between stops is there to build suspense\.

Tap the red lever knob, or the button, to spin again\.

### 4. Inside: three reels

Behind the glass sit three drums wrapped in a printed strip\. This strip has 22 stops: symbols with blank gaps between them\. The middle row, along the red payline, is the one that counts\.

The first machine of this kind, the Liberty Bell, was built in San Francisco in the 1890s\.

### 5. The random number chip

A tiny chip picks random numbers thousands of times a second, even when nobody is playing\. The instant you pull, the numbers on show are kept\. They decide the result before the reels even start\.

Tap the lever knob to catch a new set of numbers\.

### 6. The hidden, bigger reel

Each number points to a stop on a hidden “virtual reel” with many more stops than the real one\. Blanks get lots of stops; the red 7 gets just one\. So the jackpot is far rarer than the strip makes it look\.

With 1 stop in 64 on each reel, three 7s come up about once in 262,144 spins\.

### 7. Winning and paying

The prize table on the front lists the winning rows\. When the payline matches one, the machine pays out\. Coins drop from a store inside called the hopper, or the credit meter simply goes up\.

Spin as often as you like\. Most spins win nothing\.

### 8. The machine always comes out ahead

The prizes are set so that, over millions of spins, the machine keeps part of the money: often 2 to 15 cents of every dollar\. Every spin is separate, so a machine is never “due” to win\.

A slot machine is entertainment, not a way to make money\.