`RPM_2 = ( D_1 / D_2 )* RPM_1 `

Enter a value for all fields

The 2nd Pulley RPM calculator computes the RPMs of a second pulley based on the the RPMs and Diameter of the first pulley and the diameter of the second pulley.  

INSTRUCTIONS: Choose units and enter the following:

• (RPM₁) RPMs of First Pulley
• (D₁) Diameter of First Pulley
• (D2) Diameter of Second Pulley

2nd Pulley RPMs (RPM₂): The calculator returns the rotational velocity of the second pulley in revolutions per minute (RPMs).  However, this can be automatically converted to compatible units via the pull-down menu.

The Math / Science

The rotation rate of the two pulleys are interconnected by the fact of a belt or chain running on the perimeter of the two pulleys.  This means that the rotation rate of pulley 1 and its diameter will dictate the belt speed.  Based on the belt speed and the diameter of the second pulley, you can compute the rotation rate of the second pulley.  The formula for the 2nd pulley rotation rate is:

RPM₂ = (D₁/D₂)⋅RPM₁

where:

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

Simple Machine Calculators

• Lever Beam Length 
• Leverage Lift Weight 
• Fulcrum Position 
• Belt Length 
• Belt Speed
• RPMs to Linear Velocity
• RPMs from linear velocity and diameter 
• 2nd Pulley RPMs
• 2nd Pulley Diameter 
• RPM of 4th pulley on three shafts 
• 2nd Gear RPM 
• Sum of Two Lengths