Enter the diameter of the drive shaft and driven shaft into the calculator to determine the pulley system velocity ratio.

Pulley System Velocity Ratio Formula

The following equation is used to calculate the Pulley System Velocity.

VR = D1/D2
  • Where VR is the velocity ratio of the pulley system
  • D1 is the driving shaft diameter
  • D2 is the drive shaft diameter

To calculate the pulley system velocity ratio, simply divide the driving shaft diameter by the driven shaft diameter. The diameter can also be substituted for rotational speed (RPM).

What is a Pulley System Velocity Ratio?


A velocity ratio is the speed of a chain in a wide belt conveyor system compared to the speed of a shaft. The ratio is typically expressed as the number of feet per minute that the chain moves divided by the number of feet per minute that the drive shaft rotates.

In many situations, this value is expressed as a percentage.

The velocity ratio compares how fast your conveyor moves with how fast your drive shaft rotates. If you have an industrial conveyor system with an 8:1 velocity ratio, it means that your conveyor moves 8 times faster than the rotation of the drive shaft.

This can be helpful in certain situations where you need to move products quickly over long distances or through difficult terrain.