The 2nd Pulley Diameter equation calculates the diameter of a second pulley based on the RPMs and Diameter of the first pulley and the RPMs of the second pulley.

INSTRUCTIONS: Choose units and enter the following:

• (RPM₁) RPMs of Pulley 1
• (D₁) Diameter of Pulley 1
• (RPM₂) RPMs of Pulley 2

2nd Pulley Diameter (D₂):   The calculator returns the diameter of pulley 2 in meters.  However this can be automatically converted to other length units via the pull-down menu.

The Math / Science

The formula for the diameter of the second pulley is:

`D_2 = D_1*((RPM_1)/(RPM_2))`

where:

• D₂ = Diameter of second pulley
• D₁ = Diameter of first pulley
• RPM₁ = Rotation rate of first pulley
• RPM₂ = Rotation rate of second pulley

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