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SWG to mm Conversion
Pick a Standard Wire Gauge number and this page returns the matching wire diameter in millimeters and inches, along with the cross sectional area. The sizes on offer run from 7/0 through 50.
What the tool shows you
The form has a single control: a Select gauge # list with options running from 7/0 through 50. Choose a size and press Calculate — no number appears until that button is pressed.
The answers arrive in three cards below the button: the diameter in millimeters, the diameter in inches, and the cross sectional area. Copy writes a result together with its unit to the clipboard, and Clear resets the form.
SWG to mm formula
The cross sectional area comes straight out of the diameter: A = (π/4) × d², where d is the diameter in millimeters.
For the largest size in the list the tool reports SWG 7/0: d = 12.7 mm = 0.5 in, A = (π/4) × (12.7 mm)² ≈ 126.6769 mm².
A smaller gauge works the same way: SWG 27: d = 0.41656 mm = 0.0164 in, A = (π/4) × (0.41656 mm)² ≈ 0.1363 mm². Higher gauge numbers in the list stand for thinner wire, so the area drops quickly, reaching SWG 50: d = 0.0254 mm = 0.001 in, A = (π/4) × (0.0254 mm)² ≈ 0.000507 mm².
| Input | Result |
|---|---|
| Select gauge #: 7/0 | Diameter in millimeters: 12.7 mm; Diameter in inches: 0.5 in; Cross sectional area: 126.6769 mm² |
| Select gauge #: 6/0 | Diameter in millimeters: 11.7856 mm; Diameter in inches: 0.464 in; Cross sectional area: 109.0921 mm² |
| Select gauge #: 0 | Diameter in millimeters: 8.2296 mm; Diameter in inches: 0.324 in; Cross sectional area: 53.1921 mm² |
| Select gauge #: 1 | Diameter in millimeters: 7.62 mm; Diameter in inches: 0.3 in; Cross sectional area: 45.6037 mm² |
| Select gauge #: 27 | Diameter in millimeters: 0.41656 mm; Diameter in inches: 0.0164 in; Cross sectional area: 0.1363 mm² |
| Select gauge #: 50 | Diameter in millimeters: 0.0254 mm; Diameter in inches: 0.001 in; Cross sectional area: 0.000507 mm² |