Belt Length Calculator

Find the belt length between two pulleys.

Pulley 1 diameter

Pulley 2 diameter

Center distance

Belt length 45.775

Formula: L = 2C + π(D1+D2)/2 + (D1−D2)² ÷ (4C)

Step-by-step with your numbers:

1. Values used:

2. Pulley 1 diameter = 6

3. Pulley 2 diameter = 4

4. Center distance = 15

6. Belt length = 45.775

Did we solve your problem today?

Calculate the belt length needed to wrap two pulleys.

The math behind it

L = 2 × center distance + π(D1 + D2)/2 + (D1 − D2)² ÷ (4 × center distance).

6 in & 4 in pulleys, 15 in apart → ~45.8 in.

Crossed belt?

Use a different formula; this is for an open (same-direction) belt.