AWG to mm/mm² Calculator

Convert American Wire Gauge (AWG) to millimeters and square millimeters instantly. Compare standards: NEC, IEC, and BS. Calculate wire diameter, cross-sectional area, resistance, and current capacity.

Important: AWG to diameter and area conversion is purely geometric and independent of wire material. Material selection only affects resistance and current capacity calculations.

AWG
Enter AWG size (0 to 40, including half sizes like 12.5)
Select conversion direction
8 AWG
10 AWG
12 AWG
14 AWG
16 AWG
18 AWG
20 AWG
22 AWG
24 AWG

Understanding AWG (American Wire Gauge)

American Wire Gauge (AWG) is a standardized wire gauge system used predominantly in North America for the diameters of round, solid, nonferrous, electrically conducting wire. The system is based on a geometric progression between two defined diameters.

Key Formula (Material Independent):

The diameter in millimeters for a given AWG size can be calculated using:

Diameter (mm) = 0.127 × 92(36 - AWG)/39

The cross-sectional area in mm² is then calculated as:

Area (mm²) = π × (Diameter/2)2

Why AWG Conversion is Material Independent

1

Geometric Standard: AWG defines physical dimensions only - the diameter of the wire. This is purely a geometric specification that applies regardless of what material the wire is made of.

2

Material Properties: While the diameter is fixed for a given AWG, electrical properties like resistance, current capacity, and weight depend on the material. Copper and aluminum wires of the same AWG have the same diameter but different electrical characteristics.

3

Practical Implication: You can use AWG to specify wire size for any material, but you must consider material-specific properties when calculating electrical performance.

International Standards Comparison

Standard Region Base Unit Current Rating Basis Key Documents
NEC (USA) United States, Canada AWG 60°C copper, 75°C aluminum NEC 2023, Table 310.15(B)(16)
IEC (International) Europe, Asia, International mm² PVC insulation, 30°C ambient IEC 60228, IEC 60364-5-52
BS (UK) United Kingdom mm² PVC insulation, conduit in air BS 7671, BS 6004
AS/NZS (Australia/NZ) Australia, New Zealand mm² PVC insulation, 40°C ambient AS/NZS 3008.1.1
JIS (Japan) Japan mm² 60°C insulation JIS C 3307

AWG to Metric Conversion Reference

AWG Size Diameter (mm) Area (mm²) Nearest IEC (mm²) Nearest BS (mm²)
0000 (4/0) 11.68 107.2 120 120
000 (3/0) 10.40 85.0 95 95
00 (2/0) 9.27 67.4 70 70
0 (1/0) 8.25 53.5 50 50
2 6.54 33.6 35 35
4 5.19 21.2 25 25
6 4.12 13.3 16 16
8 3.26 8.37 10 10
10 2.59 5.26 6 6
12 2.05 3.31 4 4
14 1.63 2.08 2.5 2.5
16 1.29 1.31 1.5 1.5
18 1.02 0.823 1.0 1.0
20 0.812 0.518 0.75 0.75
22 0.644 0.326 0.5 0.5
24 0.511 0.205 0.3 0.3

Material-Specific Electrical Properties

NEC
NEC Standard Factors
  • Wire material (copper vs aluminum) - affects current capacity
  • Insulation type and temperature rating (60°C, 75°C, 90°C)
  • Ambient temperature correction factors
  • Installation method (in conduit, free air, bundled)
IEC
Material Resistivity Comparison
  • Copper: 1.68 × 10⁻⁸ Ω·m (better conductor)
  • Aluminum: 2.82 × 10⁻⁸ Ω·m (higher resistance)
  • Ratio: Aluminum has ~1.68 times higher resistance than copper for same size
  • Weight: Aluminum is ~30% the weight of copper for same conductivity
AWG Size NEC Copper (A) NEC Aluminum (A) IEC Copper (A) BS Copper (A)

Note: NEC values for 60°C copper and 75°C aluminum, not more than three current-carrying conductors. IEC and BS values for PVC insulation, 30°C ambient, in conduit in air.

Frequently Asked Questions

No. AWG defines the physical diameter of the wire, which is independent of the material. A 12 AWG copper wire and a 12 AWG aluminum wire have exactly the same diameter (2.05 mm) and cross-sectional area (3.31 mm²). The material only affects electrical properties like resistance, current capacity, weight, and cost.

Different standards use different assumptions about installation conditions, ambient temperatures, insulation materials, and safety factors. NEC tends to be more conservative in some aspects, while IEC and BS may have different calculation methodologies. Always use the standard applicable to your region and installation.

AWG sizes don't exactly match metric sizes. The best approach is to calculate the cross-sectional area in mm² for the AWG size, then select the nearest standard metric size. For example, AWG 12 has an area of 3.31 mm², which is closest to 4 mm² in the IEC standard. This tool provides the nearest equivalent for each standard.