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YouLoveSolar Wire Size Calculator (highly customizable) v2024.02.19.01

No longer switch between multiple tables: Choose the right wire for your custom allowable voltage drop while simultaneously taking into account ampacity, temperatures, and bundling. Click the orange button at the top of the screen to download the Excel sheet (safe: no macros / VBA code). See feature comparison table against other wire size calculators below.

  • AC/DC - 12/24/36/48/120V/... and any other custom system voltage
  • custom maximum allowable voltage drop
  • standards from either NEC (National Electrical Code) or ABYC (American Boat and Yacht Council)
  • Conductor materials: Copper or Aluminum (NEW)
  • wire insulation temperature ratings: 60/75/80/90/105/125/200C
  • custom number of conductors in a bundle for derating
  • custom ambient temperature for derating
  • custom units: feet / meter and Celcius / Fahrenheit
  • custom current
  • custom circuit length based on either one-way distance or return-trip circuit length
  • custom number of wires in parallel
  • add connector electrical contact resistances for a custom number of connectors in the circuit
  • each AWG size is vizualized with its own color for easy viewing
  • download and use locally: no dependence on an internet connection
  • Disclaimer: Use at your own risk.
  • Will not run correctly in Google Sheets and OpenOffice.
  • Feature requests or bugs: Let me know.

wire calculator screenshot.PNG

Example results when changing the allowed voltage drop from 1% to 10%:


ree Wire Sizing Tool Feature Comparison List.png
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First release
Last update
3.00 star(s) 1 ratings

Latest updates

  1. Added: Aluminum conductors and larger kcmil wires

    Added NEC 250-500 kcmil wires Added Aluminum material Added periods to version numbering
  2. minor update

    Improved comments for when running multiple wires in parallel Readability improvements "under...
  3. Added feature to run multiple wires in parallel

    Improved UI Added feature to run multiple wires in parallel

Latest reviews

doesn't run in open office
Thanks, bummer, added it to the notes.