Calculate the belt length required for a two-pulley system. Uses center distance and pulley diameters to determine the precise belt size needed for replacement or design.
Standard V-belts are often measured by outside length, but some industrial belts use pitch length. Check the belt manufacturer specs.
It should be tight enough to prevent slipping under load, but not so tight that it damages bearings. A common rule is 1/2 inch deflection per foot of span.
L = 2C + 1.57(D+d) + (D-d)²/4C