Calculator route
AWG ↔ mm² Converter
Convert American Wire Gauge and metric cross-sectional area for UK installers using imported AWG components against UK mm² specs.
Estimate only — this tool supports conversion and communication, not BS 7671 compliance sign-off.
Quick AWG presets
Accepts 4/0, 3/0, 2/0, 1/0 (or 0000, 000, 00, 0), then 1 to 40.
Result
How it's calculated
d(mm) = 0.127 × 92^((36 − AWG) / 39), area = π × (d/2)^2
Reverse mode algebraically inverts the same geometric definition and snaps to nearest AWG for practical picking.
- Estimate only — this is guidance, not a compliance verdict.
- AWG values are derived from the geometric wire-diameter definition.
Formula version: 1.0.0
UK FAQ
What's the AWG for 2.5 mm² twin and earth?
2.5 mm² maps near AWG 13. UK cable selection should still be done in mm² against BS 7671 framing.
Why doesn't AWG match a UK CSA exactly?
AWG follows a geometric progression while UK metric sizes follow a preferred mm² ladder, so exact one-to-one matches are uncommon.
Can I substitute imported AWG cable on a UK install?
Treat AWG as a bridge. Convert to mm², then verify against UK design/current-carrying checks before specifying cable.
Common pitfalls
- Treating AWG and mm² as exact equivalents. They are different sizing systems, so conversion is usually approximate.
- Picking a cable only by converted AWG. Final UK sizing must still be validated in mm² against design current, installation method, and voltage-drop limits.
- Confusing SWG with AWG on imported specs. Legacy UK SWG values are different; use the SWG lookup when the source standard is unclear.
Continue with SWG lookup or review sources and standards framing.