Wire gauge reference tool
AWG Diameter Calculator
Convert an AWG gauge into bare conductor diameter and approximate area for drawing, submittal, and field notes.
Calculate AWG Diameter
Enter an AWG size to get the approximate bare conductor diameter in inches and millimeters, with area context.
Result
Diameter
0.0808 in
Diameter
2.052 mm
Square millimeters
3.31 mm2
12 AWG
Result notes. Keep inputs, assumptions, and result together before using this value in project records.
Keep the entered values, assumptions, and result together when adding this calculation to job notes or submittal records. Final installation choices should align with the applicable code edition, equipment listing, manufacturer instructions, local amendments, and AHJ requirements.
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Formula and field context
Convert an AWG gauge into bare conductor diameter and approximate area for drawing, submittal, and field notes.
Formula context
Wire Gauge Diameter Chart
Wire gauge diameter is a bare-metal geometry reference. It is useful for identification, drawing review, and AWG math, but it is not the diameter to use for conduit fill, tray fill, cable glands, or terminal fit. Physical installation work needs the finished insulated conductor or cable outside diameter from the product data.
Formula
Diameter in inches = 0.005 x 92^((36 - AWG) / 39).Variables to keep with the result
- AWG is the gauge number.
- Diameter is nominal bare conductor diameter before insulation or jacket construction.
Formula and variables
AWG is a logarithmic gauge system, so each gauge step changes conductor diameter by a fixed ratio rather than by a fixed number of inches. This worksheet uses common AWG reference diameters and returns bare conductor diameter in inches and millimeters, plus the approximate conductor area in square millimeters. The value is a conductor reference, not an insulation outside diameter.
U.S. field context and example
AWG diameter helps when comparing wire gauge references, checking drawings, documenting lab leads, or matching a conductor-size note to a mechanical clearance question. For example, 12 AWG is about 0.0808 inches, or about 2.05 mm, as a bare conductor diameter. Insulated cable, THHN/THWN-2 conductor outside diameter, flexible cord, and assembled cable diameter can be larger and must be checked from manufacturer data when physical fit matters.
Assumptions and limits
The output is not an ampacity value and does not select a conductor for a branch circuit, feeder, motor, or service. Conductor material, insulation type, terminal temperature rating, ambient temperature, bundling, raceway fill, and voltage drop can all affect an installation decision. Use the wire gauge converter, wire-size calculator, ampacity calculator, and related charts when the question moves beyond diameter reference.
Common mistakes
Common mistakes include confusing bare conductor diameter with insulated outside diameter, using metric area as if it were an NEC conductor size, and assuming a diameter match means the conductor is suitable for the load. Keep the AWG size, diameter reference, insulation family, and manufacturer cut sheet together when the note will be used for layout or documentation.