Codewire — NEC Field Calculators for Electricians

Codewire puts the five most-used National Electrical Code (NEC) calculators in one fast, offline app, so electricians stop juggling several tools and a paper code book on the job. Every calculation gives an instant pass/fail against the code.

The five calculators

• Voltage Drop — percent drop over a run and the minimum wire size to stay within 3% / 5% (NEC 210.19, Chapter 9).
• Conduit Fill — whether conductors fit a conduit and the smallest size that passes (NEC Chapter 9, Tables 1, 4, 5).
• Conduit Bending — offsets, three- and four-point saddles, and 90° stub-ups.
• Box Fill — required cubic inches versus box volume (NEC 314.16).
• Wire Ampacity — allowable ampacity with ambient and bundling derating and termination limits (NEC 310.16, 310.15).

Pricing

The calculators are free. Codewire Pro ($6/month or $45/year, 7-day free trial) adds unlimited saved jobs, cloud sync across devices, and PDF report export.

Codewire works offline and installs to your phone's home screen. Always verify results against the NEC edition adopted by your local authority having jurisdiction (AHJ).