Two-Pulley RPM & Speed Ratio

Match driver to driven pulley by RPM, diameter, and belt length.

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

Result

Ratio

0.5

Driven RPM

875

About this tool

Enter two diameters (or teeth) and either input or output RPM, and see the partner RPM, ratio, and an estimated belt length. Targets r/CNC, r/Automotive, and r/Woodworking belt-drive debates.

Related tools

More engineering you might find useful.

Beam Span & Size Estimator

Quick-check a wood, LVL, or W-shape against deflection.

Spread Footing & Pad Sizer

Estimate a square isolated pad for axial and moment loads.

Rebar Weight & Length Calculator

Convert bar size, length, and lap into pounds and tons.

Other categories

Looking for something different? Browse the rest of the catalog.

Suggest a tool