mm² and AWG conversion equations

American Wire Gauge is a geometric diameter scale. The conversion first calculates nominal solid-wire diameter, then derives circular cross-sectional area; the inverse equation estimates the theoretical AWG number for an entered metric area.

AWG nominal diameter

d = 0.127 \times 92^{\frac{36 - n}{39}}

AWG to square millimeters

A = \frac{π d^{2}}{4} = 0.012668 \times 92^{\frac{36 - n}{19.5}}

Square millimeters to theoretical AWG

n = 36 - 19.5 \times \frac{\ln (\frac{A}{0.012668})}{\ln (92)}

where:

n: AWG gauge number; 1/0, 2/0, 3/0, and 4/0 correspond to 0, -1, -2, and -3
d: Nominal diameter of the equivalent solid round wire[mm]
A: Nominal conductor cross-sectional area[mm²]
ln: Natural logarithm used to invert the AWG area equation

Metric nominal sizes and AWG sizes are independent series. The nearest numerical area may be smaller than the entered size, so the calculator also reports a not-smaller reference.

How to convert mm² to AWG

Enter the conductor cross-sectional area in square millimeters. The calculator applies the AWG geometric equation, identifies the closest listed AWG area, and separately identifies the first AWG size whose nominal area is not smaller than the input.

Choose mm² to AWG.
Enter the marked metric conductor area.
Read the theoretical gauge and nearest listed AWG.
Use the not-smaller result when conductor area must not decrease.
Confirm the actual cable, lug, terminal, and crimp range.

mm² to AWG conversion chart

Metric and AWG sizes do not align exactly. For example, 4 mm² is mathematically closest to 11 AWG at about 4.17 mm², while 12 AWG is only about 3.31 mm². A familiar market pairing is not necessarily the closest cross-sectional-area conversion.

Metric size	Nearest AWG by area	AWG nominal area	Not-smaller AWG
0.500 mm²	20 AWG	0.518 mm²	20 AWG
0.750 mm²	18 AWG	0.823 mm²	18 AWG
1.00 mm²	17 AWG	1.04 mm²	17 AWG
1.50 mm²	15 AWG	1.65 mm²	15 AWG
2.50 mm²	13 AWG	2.62 mm²	13 AWG
4.00 mm²	11 AWG	4.17 mm²	11 AWG
6.00 mm²	9 AWG	6.63 mm²	9 AWG
10.0 mm²	7 AWG	10.5 mm²	7 AWG
16.0 mm²	5 AWG	16.8 mm²	5 AWG
25.0 mm²	3 AWG	26.7 mm²	3 AWG
35.0 mm²	2 AWG	33.6 mm²	1 AWG
50.0 mm²	1/0 AWG	53.5 mm²	1/0 AWG
70.0 mm²	2/0 AWG	67.4 mm²	3/0 AWG
95.0 mm²	3/0 AWG	85.0 mm²	4/0 AWG
120.0 mm²	4/0 AWG	107.2 mm²	Above 4/0 AWG

How to convert AWG to mm²

Select an AWG size from 40 AWG through 4/0 AWG. The result shows its nominal solid-wire area, nominal solid-wire diameter, closest common metric area, and the first metric nominal size that is not smaller.

12 AWG ≈ 3.31 mm²

1/0 AWG ≈ 53.5 mm²

4/0 AWG ≈ 107.2 mm²

AWG to mm² conversion chart

This reference table covers every calculator selection from 40 AWG through 4/0 AWG. Diameter is the nominal solid-wire reference, not the outside diameter of a stranded or insulated cable.

AWG size	Cross-sectional area	Solid-wire diameter
40 AWG	0.0050 mm²	0.0799 mm
39 AWG	0.0063 mm²	0.0897 mm
38 AWG	0.0080 mm²	0.101 mm
37 AWG	0.0100 mm²	0.113 mm
36 AWG	0.0127 mm²	0.127 mm
35 AWG	0.0160 mm²	0.143 mm
34 AWG	0.0201 mm²	0.160 mm
33 AWG	0.0254 mm²	0.180 mm
32 AWG	0.0320 mm²	0.202 mm
31 AWG	0.0404 mm²	0.227 mm
30 AWG	0.0509 mm²	0.255 mm
29 AWG	0.0642 mm²	0.286 mm
28 AWG	0.0810 mm²	0.321 mm
27 AWG	0.102 mm²	0.361 mm
26 AWG	0.129 mm²	0.405 mm
25 AWG	0.162 mm²	0.455 mm
24 AWG	0.205 mm²	0.511 mm
23 AWG	0.258 mm²	0.573 mm
22 AWG	0.326 mm²	0.644 mm
21 AWG	0.411 mm²	0.723 mm
20 AWG	0.518 mm²	0.812 mm
19 AWG	0.653 mm²	0.912 mm
18 AWG	0.823 mm²	1.02 mm
17 AWG	1.04 mm²	1.15 mm
16 AWG	1.31 mm²	1.29 mm
15 AWG	1.65 mm²	1.45 mm
14 AWG	2.08 mm²	1.63 mm
13 AWG	2.62 mm²	1.83 mm
12 AWG	3.31 mm²	2.05 mm
11 AWG	4.17 mm²	2.30 mm
10 AWG	5.26 mm²	2.59 mm
9 AWG	6.63 mm²	2.91 mm
8 AWG	8.37 mm²	3.26 mm
7 AWG	10.5 mm²	3.66 mm
6 AWG	13.3 mm²	4.12 mm
5 AWG	16.8 mm²	4.62 mm
4 AWG	21.2 mm²	5.19 mm
3 AWG	26.7 mm²	5.83 mm
2 AWG	33.6 mm²	6.54 mm
1 AWG	42.4 mm²	7.35 mm
1/0 AWG	53.5 mm²	8.25 mm
2/0 AWG	67.4 mm²	9.27 mm
3/0 AWG	85.0 mm²	10.4 mm
4/0 AWG	107.2 mm²	11.7 mm

Conversion is not ampacity selection

Equal or similar cross-sectional area does not prove equal ampacity, voltage-drop performance, terminal compatibility, or code compliance. Conductor material, strand class, insulation temperature, installation method, ambient temperature, grouping, and terminal ratings still control the final selection.

AWG Wire Size Calculator Cable Lug Selector Voltage Drop Calculator

Assumptions

AWG range is 40 AWG through 4/0 AWG
Calculated diameter is the nominal solid round conductor reference
Metric comparison uses common IEC-style nominal cross-sectional areas

Important Warnings

A numerical conversion does not make metric and AWG cables, lugs, terminals, or crimp dies interchangeable.
Stranded conductor outside diameter depends on strand class, compaction, insulation, and manufacturer construction; it cannot be inferred from conductor area alone.

mm² to AWG & AWG to mm² Converter

mm² and AWG conversion equations

where:

How to convert mm² to AWG

mm² to AWG conversion chart

How to convert AWG to mm²

AWG to mm² conversion chart

Conversion is not ampacity selection

Assumptions

Important Warnings

FAQ

mm² to AWG & AWG to mm² Converter

mm² and AWG conversion equations

where:

How to convert mm² to AWG

mm² to AWG conversion chart

How to convert AWG to mm²

AWG to mm² conversion chart

Conversion is not ampacity selection

Assumptions

Important Warnings

FAQ

Continue the selection workflow.

AWG Wire Size Calculator

Cable Lug Selection Calculator

Voltage Drop Calculator