Calculating Drive Belt Length

Given two pulleys, a known distance apart.
The diameter of each pulley is known.

This page calculates the length of the belt required
to wrap both pulleys with no slack.

You can also enter a belt length, and calculate the
distance required between pulleys.

This program does not take into account stretch or
wear of belt or pulleys.
Belt Length Calculator
Note: All dimensional units must be the same.

  Pulley Diameters: and
  Distance between Pulley Centers:
  Belt length:
Intermediate Results

Pulley Circumferences: and

Belt length breakdown:
 straight legs:
 wrap lengths: and

Note: If there is a large size difference between the two pulleys, you may want to avoid minimum spacing between them as this will decrease the wrap length around the smaller pulley, decreasing it's loading capability.