Pulley Calculator - Centres RPM, Belt Length and Speed
Large Pulley Diameter
Small Pulley Diameter
Pulley Centre Distance
Gap Small Pulleys May Touch
Enter Large and Small Pulley Diameters and Pulley Centre Distance.
Drag Centres slider to re-calculate and animate diagram.
Select RPM Large or RPM Small and enter RPM to calculate corresponding pulley RPM.
Drag sliders to animate diagrams.
If you know any 3 values (Pulley sizes or RPM) and need to calculate the 4th, enter the 3 known values and hit Calculate to find the missing value.
For example, if your small pulley is 80mm diameter, and spins at 1000 RPM, and you need to find the second pulley size to spin it at 400 RPM,
Enter Pulley1 Size 80, Pulley 1 RPM 1000, Pulley 2 RPM 400, and hit Calculate to find the second pulley diameter.
Metric or Imperial
The main (larger) navigation menu tabs are for the Metric versions of calculators.
If there is an Imperial (Feet and Inches) version, under the main Metric tab will be a smaller Imperial tab.
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Questions or Suggestions? ph: +61 7 40987645
ALWAYS CHECK WITH YOUR LOCAL BUILDING AUTHORITY BEFORE LAYING OUT OR BUILDING ANYTHING AND FOLLOW ALL LOCAL CODES. VERIFY ALL DIMENSIONS AND ANGLES BEFORE CONSTRUCTION.
All calculators on this site are GEOMETRIC only. Check local regulations for sizes, spacings and all engineering requirements.