AWG 25 Wire

Diameter 0.0179″
Millimeters 0.455 mm
Cross-section 320 cmil
mm² 0.1624

Nominal bare-conductor dimensions per ASTM B258. AWG is geometric: d = 0.005 × 92(36−n)/39 in with n = 25; 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 25
23 0.0226″ 0.574 +0.0047″
24 0.0201″ 0.511 +0.0022″
25 0.0179″ 0.455
26 0.0159″ 0.404 −0.0020″
27 0.0142″ 0.361 −0.0037″

Measuring sheet metal, not wire? Sheet uses a different gauge scale — see 25 gauge sheet (steel: 0.0209″).

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