Estimate the Length of a Wire

Estimate the Length of a Wire

You can use this calculator to estimate how much wire is left on a spool.

  1. Start by measuring the resistance of the length of wire. Use an ohmmeter to measure the resistance of the wire. If you use a 2-wire measurement the calculator assumes you have 0.2 ohms of lead resistance. If you make a four-wire measurement the estimate will be more accurate.
  2. Enter the resistance into the calculator.
  3. Select the wire gauge on the calculator.
  4. Click the “Calculate Wire Length” button.
spools of wire


Estimated Wire Length

If you used a 2-wire measurement (assuming 0.2 ohms lead resistance):
Expect more than ___ feet  and less than ___ feet (___ to ___ meters)

If you used a 4-wire measurement:
Expect more than ___ feet and less than ___ feet (___ to ___ meters)