Conduit Size Calculator

Overfilling a conduit makes pulling wire brutal and violates NEC fill rules. Add each conductor's AWG and insulation, and get the minimum EMT conduit trade size.

📋 NEC-based

Uses Chapter 9 area tables: 40% fill for 2+ conductors, with standard THHN/THWN dimensions.

🔧 Mixed sizes

Add as many conductors as you like at any AWG — the calculator sums their actual areas.

🚚 Pull-friendly

Staying at or under 40% fill keeps wire pulls smooth and protects the insulation.

🔒 Private

All calculations run locally in your browser.

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Wire it safely.