Wire AWG Size Conversion Calculator

AWG to Metric Conversion Guide: Wire Sizes Explained

Navigating between American Wire Gauge (AWG) and metric measurements ($mm$ or $mm^2$) can be challenging. While AWG is the standard in North America, the UK and the rest of the world typically use the metric system.

Whether you are an American customer faced with metric options, or a UK customer trying to match a specific AWG requirement, this guide bridges the gap.

Quick Conversion Table: AWG to Metric

Use this table to find the closest standard metric cable size for your AWG requirement. Note that AWG does not convert perfectly to metric round numbers; we have recommended the closest suitable "Available Cable Size" for purchase.

AWG #	Diameter (mm)	Area (mm²)	Recommended Metric Size
4/0 (0000)	11.68	107.22	120 $mm^2$
3/0 (000)	10.40	85.03	95 $mm^2$
2/0 (00)	9.27	67.43	70 $$

⚠️ Safety Note: For mains voltage applications (110v, 230v, etc.), we suggest a minimum conductor size of 0.5mm² (AWG 23 and up). Smaller cables (AWG 24-40) are generally reserved for low-voltage applications such as audio, video, telephone, and data signal cabling.

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Understanding the AWG Standard

The American Wire Gauge (AWG) system was developed by the Brown & Sharpe Company—a leading manufacturer of machinist technology—and was formally adopted as an industry standard in 1857.

Unlike metric sizing, where the number represents the actual size (width or area), AWG is a "retrograde" system: the higher the number, the thinner the wire.

The Conversion Formula

Because AWG is based on a geometric progression rather than round metric numbers, converting it requires a specific mathematical formula.

To calculate the diameter ($d_n$) of an $n$ gauge wire in millimeters:

$d_n (mm) = 0.127 \text{ mm} \times 92^{\frac{36-n}{39}}$

Small Electronics Wire Sizes (AWG 23-40)

These sizes are typically used for data, signal, and winding applications.

AWG #	Diameter (mm)	Area (mm²)
23	0.57	0.26
24	0.51	0.20
25	0.45	0.16
26	0.40	0.13
27	0.36	0.10
28	0.32	0.08
29	0.29	0.06
30	0.25	0.05
32	0.20	0.03
34	0.16	0.02
36	0.13	0.01
38	0.10	0.008
40	0.08	0.005