Millwrights

Pulley RPM Calculator

Calculate driven RPM from driver RPM and pulley diameters.

Driver RPM Driver pulley diameter (in) Driven pulley diameter (in)

Driven RPM875 rpmRatio: 0.500

Speed change50%

Driver1,750 rpm

Driver pulley4.000"

Driven pulley8.000"

Estimate assumes no belt slip and uses pitch diameter style math. Verify sheave data, belt type, tension, guarding, and machine limits.

How to use this tool

Pulley RPM Calculator guide

Calculate driven RPM from driver RPM and pulley diameters. Enter the known field measurements and use the result as a fast estimate or layout reference.

Always verify the print, code requirements, equipment manual, material specification, site conditions, and qualified trade judgment before using calculator results on a real job.