AWG to mm²

American wire gauge is the US electrician's unit of wire size — 12 AWG is the standard household circuit wire, 14 AWG feeds lights, and the number drops as the wire gets thicker. The metric world sizes the same wire in square millimeters: 12 AWG is 3.31 mm², 14 AWG is 2.08 mm², and 10 AWG is 5.26 mm². This converter is the translation layer for imported equipment and international specs.

By EnginStack Engineering Team | Verified by engineers, built on NIST metrology standards About →
AWG
— mm²
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Constants verified against NIST Special Publication 811 (Guide for the Use of the International System of Units) and the 1959 International Yard and Pound Agreement. All values are exact — none are rounded approximations.

AWG to mm²

The AWG scale is a geometric progression: each gauge step is a fixed ratio of diameters (92^(1/39) ≈ 1.123), which is why the numbers are small for thick wire and large for thin wire. The exact formula — d(mm) = 0.127 × 92^((36−AWG)/39) — comes from the 1857 definition: 0000 AWG (4/0) is 0.46 in diameter and 36 AWG is 0.005 in, with 39 logarithmic steps between. The area in mm² is π/4 × d². Every ampacity table, wire connector, and terminal spec eventually needs this conversion when US and metric hardware meet.

mm² = π/4 × (0.127 × 92^((36 − AWG)/39))²
12 AWG = 3.31 mm²  ·  14 AWG = 2.08 mm²  ·  10 AWG = 5.26 mm²
The formula reproduces the 1857 AWG definition exactly.

Common AWG to mm² Values

AWGmm²Context
10 AWG—5.26 mm²30 A circuits, large feeders.
12 AWG—3.31 mm²15–20 A household circuits.
14 AWG—2.08 mm²15 A lighting circuits.
16 AWG—1.31 mm²Extension cords.
18 AWG—0.82 mm²Lamp cords, low current.

Engineering Context

AWG-to-mm² is the wire-sizing bridge between the electric hub and the metric wire world. The current ratings connect to watts to amps — a 15 A breaker is what 12 AWG protects at 120 V — and the reverse conversion lives on mm² to AWG. Voltage-drop calculations on the same wire use the ohms to volts page.

More: mm² to AWG · W to A · Ω to V · Electric Hub

Related Unit Converters

Mm2 To Awg Watts To Amps Ohms To Volts Electric Converters

Frequently Asked Questions

What is 12 AWG wire in mm²?

Exactly 3.31 mm². It is the standard US household circuit wire, rated for 15–20 amps at 120 V depending on insulation and installation.

How does the AWG numbering work?

Larger number = thinner wire. Each gauge step multiplies the diameter by 92^(1/39) ≈ 1.123, and every three steps roughly halves the area. 10 AWG (5.26 mm²) is double the area of 13 AWG.

Why do US and metric wire specs use different units?

Same path dependence as every unit pair: the US built its electrical infrastructure on AWG (from the 1857 Brown & Sharpe standard), while the metric world sizes by cross-sectional area in mm². Both are exact; only the label differs.