Mechanical / 03
Pulley RPM Calculator
Calculate driven pulley speed in rpm using driver speed and pulley pitch diameters.
How it works
n2 = n1 × D1 / D2
A 100 mm driver at 1,500 rpm driving a 200 mm pulley produces 750 rpm.
FAQ
Does belt slip affect the result?
Yes. This calculation assumes no slip.
Must diameters be in mm?
The page uses mm. Both diameters must use the same unit.
How do I reduce speed?
A driven pulley larger than the driver reduces output speed.