Electrical Wire Size Calculator

Min by ampacity (NEC 310)
Min by voltage drop
Recommended

NEC 310.16, 75°C copper THWN. Aluminum derated. Always verify with local code & a licensed electrician.

About this tool

Electrical Wire Size Calculator is a single-purpose utility on instant.tw, a free toolbox of calculators, converters, generators, and quick lookups. Everything works in your browser — nothing is uploaded, nothing is stored on a server unless explicitly noted.

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