Pulley Calculator - Centers - RPM - Belt Length and Speed
Gap Small Pulleys May Touch
Enter any 3 known values to calculate the 4th
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 6" diameter, and spins at 1000 RPM, and you need to find the second pulley size to spin it at 500 RPM,
Enter Pulley1 Size 6, Pulley 1 RPM 1000, Pulley 2 RPM 500, and hit Calculate to find the second pulley diameter.
Enter inches as decimal or fraction with space or slash. eg: 6.75 or 6 3/4 or 6 3 4
Multiple Pulleys - RPM Reduction
To calculate multiple pulley sets, where the first driven (large) pulley shaft drives the second driver (small) pulley, and so on,
enter first (small) driver pulley RPM and pulley set diameters and centers separated by commas and - as shown below.
The RPM of the first driven (large) pulley is transferred to second set small (driver) pulley and so on. The sets of pulleys will be drawn at the bottom of the page with each set RPM
reductions and total RPM reduction through all entered sets.
In this instance, the initial small driver pulley RPM is 2000.
The small pulley diameter is 3", large pulley diameter is 12.5" and centers is 24".
The second set small pulley diameter is 4", large pulley diameter is 12" and centers is 12.5".
identical sets at current diameters, centers and RPM
If you're cutting concrete, stone or ANYTHING and there's DUST - DON'T TAKE THE RISK
Don't cut it, or cut it wet so there's NO DUST - Silicosis Sucks
How should we spell it?
What do we think? - They're 2 different things:
A Meter is a device to measure things - like a Volt Meter or a Parking Meter
A Metre is about 3'-3~3/8"
Although diameter and perimeter as measurements - don't seem to fit very well
If the US ever goes Metric, you'll be able to use a Meter to measure Meters - A Meter Meter
All Imperial inputs and dimensions are actual physical finished sizes(unless otherwise noted)
All Metric Inputs in Millimetres(unless otherwise noted)