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AWG Wire Gauge / Ampacity Calculator

Find the minimum AWG wire gauge and equivalent mm² cross-section for a given current and run length, per NEC ampacity tables

Electrical
📋NFPA 70 NEC Table 310.15(B)(16) — Ampacity at 60°C/75°C; IS 694:2010 (PVC insulated cables)
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Estimation tool only. Results are indicative — not a substitute for professional engineering design or site-specific survey. Always verify with a qualified civil, structural, or MEP engineer before ordering materials or commencing construction.

Calculate

Results are estimates only. Verify with a qualified engineer before use.

Formula

Voltage drop (V) = (2 × L × I × ρ) / A
Where ρ = resistivity of copper = 1.724×10⁻⁸ Ω·m

Maximum allowed voltage drop = 3% of supply voltage

Required cross-section: A (mm²) = (2 × L × I × ρ) / (0.03 × V_supply)

AWG to mm² conversion:
14AWG=2.08  12AWG=3.31  10AWG=5.26  8AWG=8.37
6AWG=13.3   4AWG=21.1   2AWG=33.6   1/0AWG=53.5
ILoad current (A)
LOne-way cable run length (m)
VSupply voltage (V)
ρCopper resistivity (1.724×10⁻⁸ Ω·m)
AConductor cross-section (mm²)

Reference Standard

NFPA 70 NEC Table 310.15(B)(16) — Ampacity at 60°C/75°C; IS 694:2010 (PVC insulated cables)

Practical Tips

  • •Always verify with a licensed electrician — local codes (IS 3043, CPWD specs) may require derating for bundled cables or high ambient temperature.
  • •For aluminium conductors (common in India for distribution), use one gauge larger than copper equivalent — aluminium has ~60% of copper's conductivity.
  • •Motor circuits should be sized at 125% of full-load current per NEC / IS 732 for continuous load safety.
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