`BL = (D_D+D_d)*pi/2 +(L*2)+ ( (D_D-D_d)^2 / (L*4) )`

Enter a value for all fields

The Length of a Belt calculator computes the length of a belt that goes around two pulleys Belt length around two pulleys. based on the pulley diameters (D_D and D_d) and the distance between the axles (L).

INSTRUCTIONS:  Choose units and enter the following:

• (D_D) Diameter of First Pulley
• (D_d) Diameter of Second Ppulley
• (L) Distance between Axles

Belt Length (BL): The calculator return the belt length (BL) in inches.  However, this can be automatically converted to other length units via the pull-down menu.

The Math

The length of a belt on two pulleys formula is: 

`BL =  (D_D+D_d)*pi/2 +(L*2)+ ( (D_D-D_d)^2 / (L*4) )`

where:

• BL is the belt length
• D_D is the diameter of the first pulley.
• D_d is the diameter of the second pulley.
• L is the distance between the axles. 

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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
• Second Gear Torque
• Leadscrew Torque (lift)

References

• Handyman In~Your~Pocket page 42 :(Young and Glover)2012 published by Sequoia Publishing Inc of Littleton, Colorado, U.S.A.