Technical Note TN-001 · Standards

Wire Gauge Chart: SWG, AWG and Millimetres

A gauge number alone does not give you a diameter. The same number is a different size in SWG and in AWG. Always name the system, or give the diameter in millimetres.

Published: 2026-11-06
Revision: B

Specify the gauge system

SWG and AWG assign different diameters to the same number. A higher number means a thinner wire within either system. Metric specifications state the diameter directly.

For example, 22 SWG is 0.7112 mm; 22 AWG is approximately 0.644 mm. Do not substitute one for the other without checking the required diameter.

Converter

Gauge number

SWG–AWG–

Diameter in mm

Nearest SWG–Nearest AWG–

Chart, gauge 14–36

The chart gives nominal solid-wire diameters. SWG uses a table of fixed values. AWG diameters are calculated as 0.127 × 92 raised to the power of ((36 − gauge) / 39), in millimetres and rounded for display. These are size conversions, not electrical current ratings or manufacturing tolerances.

Gauge	SWG mm	SWG in	AWG mm	AWG in
14	2.032	0.0800	1.628	0.0641
15	1.829	0.0720	1.450	0.0571
16	1.626	0.0640	1.291	0.0508
17	1.422	0.0560	1.150	0.0453
18	1.219	0.0480	1.024	0.0403
19	1.016	0.0400	0.912	0.0359
20	0.914	0.0360	0.812	0.0320
21	0.813	0.0320	0.723	0.0285
22	0.711	0.0280	0.644	0.0253
23	0.610	0.0240	0.573	0.0226
24	0.559	0.0220	0.511	0.0201
25	0.508	0.0200	0.455	0.0179
26	0.457	0.0180	0.405	0.0159
27	0.417	0.0164	0.361	0.0142
28	0.376	0.0148	0.321	0.0126
29	0.345	0.0136	0.286	0.0113
30	0.315	0.0124	0.255	0.0100
31	0.295	0.0116	0.227	0.0089
32	0.274	0.0108	0.202	0.0080
33	0.254	0.0100	0.180	0.0071
34	0.234	0.0092	0.160	0.0063
35	0.213	0.0084	0.143	0.0056
36	0.193	0.0076	0.127	0.0050

What to put on an order

State SWG or AWG, or specify the diameter in millimetres.
State the permitted tolerance. An example tolerance is not automatically an HSYWIRE production specification.
For coated wire, say whether the diameter refers to the metal core or the finished product.

See measuring coated wire for the distinction between core and finished diameter.

Reference

Wire gauge comparison table from Chaplin Wire. Minor differences in displayed AWG values can result from rounding. Confirm the metric diameter on the order.