AWG to mm² Calculator
Convert American Wire Gauge (AWG) to cross-section in mm² — and back — with diameter and a typical copper ampacity for quick sizing.
Ampacity is a rough 75°C copper guide — always confirm against NEC 310.16 and your conditions.
How this conversion works
d(mm) = 0.127 × 92^((36 − n) ÷ 39); area = π/4 × d².Each 3-gauge step doubles the area; each 6 steps roughly halves the diameter. Going the other way, the calculator returns the nearest standard AWG for your mm².
AWG and mm² describe the same wire
American Wire Gauge is a step scale — a smaller number means a thicker wire — while the metric world sizes cable by its actual cross-section in square millimetres. Datasheets, panels and controllers mix the two, so converting is a routine step when you size solar cable or check a voltage drop.
Handy reference points
14 AWG ≈ 2.1 mm², 12 AWG ≈ 3.3 mm², 10 AWG ≈ 5.3 mm², 8 AWG ≈ 8.4 mm², 6 AWG ≈ 13.3 mm², 4 AWG ≈ 21.2 mm², and 1/0 AWG ≈ 53.5 mm². Note that a nominal metric size (say 6 mm²) rarely equals an AWG exactly — pick the next size up when in doubt.
Frequently asked questions
6 AWG is about 13.3 mm² in cross-section, with a diameter close to 4.1 mm.
Thinner. AWG runs backwards: the larger the number, the smaller the wire. 10 AWG is thicker than 14 AWG.
They are two independent standards. A common metric size such as 6 mm² sits between 10 and 8 AWG, so exact equivalence is rare; choose the next larger size for safety.
Treat it as a starting guide for 75°C copper in free air. Real ampacity depends on insulation temperature rating, ambient heat and how many conductors are bundled, so confirm against NEC Table 310.16.
Sources & standards
Wire sizing here follows the same gauge specification and code ampacity tables installers and cable datasheets use on both sides of the AWG/metric divide.
- ASTM B258-18 — Standard Specification for Standard Nominal Diameters and Cross-Sectional Areas of AWG Sizes of Solid Round Wires — ASTM International
Defines the diameter and area progression this converter's AWG formula is built from. - NFPA 70 (National Electrical Code), Table 310.16 — National Fire Protection Association
Source of the copper ampacity ranges this calculator uses as a rough sizing guide. - IEC 60228 — Conductors of insulated cables — International Electrotechnical Commission
The international metric (mm²) cable-sizing standard this tool converts AWG into. - NIST Special Publication 811 — Guide for the Use of the International System of Units (SI) — National Institute of Standards and Technology
Reference for the mm² unit and metric rounding used throughout the conversion.