AWG 28 Wire

Diameter 0.0126″
Millimeters 0.320 mm
Cross-section 159 cmil
mm² 0.0804

Nominal bare-conductor dimensions per ASTM B258. AWG is geometric: d = 0.005 × 92(36−n)/39 in with n = 28; area is derived from the diameter. Ampacity depends on insulation, bundling, and the electrical code in force — it is a property of the installation, not the gauge.

Neighboring gauges

AWG Diameter mm vs AWG 28
26 0.0159″ 0.404 +0.0033″
27 0.0142″ 0.361 +0.0016″
28 0.0126″ 0.320
29 0.0113″ 0.287 −0.0013″
30 0.0100″ 0.254 −0.0026″

Measuring sheet metal, not wire? Sheet uses a different gauge scale — see 28 gauge sheet (steel: 0.0149″).

Data provenance. ASTM B258, Standard Specification for Nominal Diameters of AWG Sizes (ASTM International). See all data sources.