# Chain Drive Ratio Calculator

Find the ratio of a chain and sprocket drive for a bicycle with this Chain Drive Ratio Calculator.

## How do you calculate the chain sprocket ratio?

The ratio in a drive system is represented in reference to the number 1. A ratio of 2 to 1 would be signified by 2:1. A ratio of 1/4 to one would be signified by .25:1.

To find the total ratio, use the equation: Ratio = (Radius of Driven Sprocket) / (Radius of Drive Sprocket)

Example: On a bicycle, the sprocket that is attached to the pedals is the drive sprocket and is 4 inches in radius. The driven sprocket at the rear wheel is 2 inches in radius. What is the total ratio?

Ratio = 2 / 4

Calculated out this drive has a .5:1 ratio. For every full revolution of the pedals, the rear wheel turns 2 revolutions.