AWG 8 Wire

Diameter 0.1285″
Millimeters 3.264 mm
Cross-section 16,512 cmil
mm² 8.37

Nominal bare-conductor dimensions per ASTM B258. AWG is geometric: d = 0.005 × 92(36−n)/39 in with n = 8; 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 8
6 0.1620″ 4.115 +0.0335″
7 0.1443″ 3.665 +0.0158″
8 0.1285″ 3.264
9 0.1144″ 2.906 −0.0141″
10 0.1019″ 2.588 −0.0266″

Measuring sheet metal, not wire? Sheet uses a different gauge scale — see 8 gauge sheet (steel: 0.1644″).

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