What is Codewire?

Codewire is a field reference app for electricians. It replaces juggling several apps and a paper code book by putting the five most-used National Electrical Code calculators in one fast, offline, mobile-first tool with instant pass/fail.

How to use it

  1. Enter values you already have — wire size, amps, run length, box size. It's a calculator, not a measuring tool.
  2. Each tool runs the NEC formula and tables and shows a clear pass / fail as you type.
  3. Save calculations to jobs; everything works offline.

The five calculators are voltage drop, conduit fill, conduit bending, box fill and wire ampacity, based on the NEC 2023 edition. The calculators are free; Codewire Pro ($6/month or $45/year) adds unlimited saved jobs, cloud sync and PDF export.

Frequently asked questions

Is Codewire free?

Yes. All five NEC calculators are free, with up to two saved jobs on your device. Codewire Pro ($6/month or $45/year) adds unlimited jobs, cloud sync across devices, and PDF report export.

Does Codewire work offline?

Yes. It's an installable app that runs entirely on your device, so the calculators work in basements and job sites with no signal.

All Codewire calculators · Free for electricians. Verify against the NEC edition adopted by your local AHJ.