Enter the outer diameter and the wire diameter into the Coil Length Calculator. The calculator will evaluate the Coil Length. 

Coil Length Formula

The following two example problems outline the steps and information needed to calculate the Coil Length.

CL = (OD-WD) * pi
  • Where CL is the Coil Length (length per coil)
  • OD is the outer diameter 
  • WD is the wire diameter 

To calculate the coil length, subtract the wire diameter from the outer diameter, then multiply by pi.

How to Calculate Coil Length?

The following example problems outline how to calculate Coil Length.

Example Problem #1:

  1. First, determine the outer diameter.
    • The outer diameter is given as: 5.
  2. Next, determine the wire diameter.
    • The wire diameter is provided as: 3.
  3. Finally, calculate the Coil Length using the equation above: 

CL = (OD-WD) * pi

The values provided above are inserted into the equation below and computed.

CL = (5-3) * pi = 6.28 (length per coil)

Example Problem #2: 

For this problem, the variables required are provided below:

outer diameter = 6

wire diameter = 4

Test your knowledge using the equation and check your answer with the calculator..

CL = (OD-WD) * pi = ?