Wire gauge without the guesswork

How it works

Wire gauge numbers identify a particular sizing system, not a universal diameter. SWG and AWG assign different diameters to the same number. The old article’s suggestion that American publications generally use SWG was misleading; verify which system a project specifies.

For a coil, the conductor diameter and the outside diameter over enamel are different measurements. The latter influences winding pitch and whether the expected number of turns fits on a former.

The original page linked to externally hosted illustrations. Those files are absent from the backup; the text has been restored without substitute images.

On the bench

Use the labeled SWG reference table below for common sizes. Do not use it to choose current capacity: that also depends on insulation, temperature, installation, and duty cycle.

Resources & provenance

Rewritten from the original articles/tut/d3mn6sf_tut003.php page. Component values and historical performance claims have not been independently bench-tested.