Transmission belt length and enclosing area

On this page formulas and a tool to calculate the length of a transmission belt and its enclosing area, given the radiuses of the two circles and the distance between the centers of the circles.

Transmission belt

Formulas

Formulas and derivation (LaTeX source)

Tool

Both . and , can be used as decimal separator.

r1:
r2:
d:
Length:
Area: