Wire Size Calculator — NEC, IEC, BS, AS/NZS | WireStandard

Calculate the correct wire size for your circuit. Enter current, distance and voltage to get recommended AWG and mm² for NEC, IEC, BS and AS/NZS standards simultaneously.

Current (A)

Voltage (V)

One-way Distance (m)

Max Voltage Drop (%)

Standard

AWG

Area (mm²)

Ampacity (A)

Volt Drop (V)

Drop %

Out of table range — consult engineer

Accuracy ±3%: DC resistivity is idealized copper. Actual NEC Chapter 9 Table 8 values (stranded, uncoated) run 1–3% higher. For life-safety feeders add a 10% safety margin on voltage-drop headroom, or consult a licensed engineer.

ρ(copper, 20 °C) = 0.01724 Ω·mm²/m (IACS). Results show the smallest wire meeting both voltage-drop and ampacity requirements for each standard. Use the temperature selector at 75 °C for NEC 75 °C operating conditions.