Timing Belt Pulley Design Calculator

We can form the following definitions and equations:

$N$ = Number of teeth on pulley.

$P$ = Pitch of Belt (distance between teeth).

$C_b$ = Circumference of belt.

$D_b$ = Diameter of belt.

$D_{po}$ = Outer Diameter of pulley.

$D_{pi}$ = Inner Diameter of pulley.

$T_b$ = Thickness of belt, measured from tooth valley to the flat side of the belt.

$H_t$ = Height of the tooth on the belt.

Equations:

$C_b = N \cdot P$

$D_b = \frac{C_b}{\pi}$

$D_{po} = D_b - 2 \cdot T_b$

$D_{pi} = D_{po} - 2 \cdot H_t$