Enter the crank pulley diameter, supercharger pulley diameter, and the engine RPM into the calculator to determine the supercharger RPM.

Supercharger RPM Formula

The following equation is used to calculate the Supercharger RPM.


  • Where SCRPM is the supercharger RPM
  • CD is the crank pulley diameter (in)
  • SCD is the supercharger pulley diameter (in)
  • ERPM is the engine RPM

What is a Supercharger RPM?


A supercharger RPM is the rotational speed at which a supercharger moves when subjected to a given RPM and a given crank to supercharger pulley ratio.

How to Calculate Supercharger RPM?

Example Problem:

The following example outlines the steps and information needed to calculate Supercharger RPM.

First, determine the crank diameter. For this example, the crank diameter is measured to be 4.5 inches.

Next, determine the supercharger diameter. The supercharger diameter for this problem is measured to be 3.5 inches.

Next, determine the current or max engine rpm. In this case, we are looking at max RPM, and it is found to be 5,000.

Finally, calculate the supercharger RPM using the formula above:


SCRPM = 4.5 / 3.5 * 5,000

SCRPM = 6428.57