Belts & Pulleys
Pulley RPM Calculator
Use driver speed and the two pulley diameters to estimate the driven shaft speed for an ideal belt drive.
Inputs
Formula
Driven pulley speed
Worked example
Using the default values shown in the calculator, the same formula gives the following result. This is a quick sanity check for the calculation, not a design recommendation.
Inputs
- Driver speed
- 1,750 rpm
- Driver pulley diameter
- 100 mm
- Driven pulley diameter
- 250 mm
Result
- Driven speed
- 700 rpm
Related calculators
Continue your workflow with a related calculation.
Belts & Pulleys
Pulley Ratio Calculator
Calculate belt-drive speed ratio from driver and driven pulley diameters.
Belts & Pulleys
Pulley Diameter Calculator
Calculate the driven pulley diameter needed for a target RPM.
Belts & Pulleys
Belt Speed Calculator
Calculate belt linear speed from pulley diameter and rotational speed.
Power, Torque & Speed
Torque from Power and RPM Calculator
Calculate shaft torque from mechanical power and rotational speed.
Frequently asked questions
Does this include belt slip?
No. The result is the ideal kinematic speed. Real drives may run slightly slower because of slip or belt deformation.
What happens when the driven pulley is larger?
A larger driven pulley reduces driven RPM relative to the driver.