AWG to mm² and AWG to mm converter
Convert between AWG gauge numbers, millimetre conductor diameter and square-millimetre cross-section using the standard geometric definition the gauge system is built on.
Definition: d(mm) = 0.127 × 92(36 − n) / 39. This is the standard's arithmetic definition, enter either side and the other follows.
Result
AWG
-
Diameter
-mm
Cross-section
-mm²
| AWG | Diameter (mm) | Cross-section (mm²) |
|---|---|---|
| 8 | 3.264 | 8.3656 |
| 10 | 2.588 | 5.2612 |
| 12 | 2.053 | 3.3088 |
| 14 | 1.628 | 2.0809 |
| 16 | 1.291 | 1.3087 |
| 18 | 1.024 | 0.8230 |
| 20 | 0.812 | 0.5176 |
| 22 | 0.644 | 0.3255 |
| 24 | 0.511 | 0.2047 |
| 26 | 0.405 | 0.1288 |
| 28 | 0.321 | 0.0810 |
| 30 | 0.255 | 0.0509 |
| 32 | 0.202 | 0.0320 |
| 34 | 0.160 | 0.0201 |
| 36 | 0.127 | 0.0127 |
The table spans the range that matters for instrument and thermocouple conductors. Values are the standard's geometric definition, not a measurement of any particular spool, a drawn conductor also carries a diameter tolerance.
Frequently Asked Questions (FAQ)
How is AWG converted to millimetres?
By the standard geometric definition the gauge system is built on: the diameter in millimetres is 0.127 multiplied by 92 raised to the power of (36 − n) divided by 39, where n is the AWG number. AWG 36 is defined as 0.127 mm and each step changes the diameter by a fixed ratio, so the conversion is arithmetic rather than a measurement.
Why does thermocouple wire get sold in millimetres instead of AWG?
Because the drawing process and the tolerance class are set in metric diameters, and the applications that specify thermocouple wire, IEC 60584-1, most furnace and process instrumentation, work in millimetres. We stock and quote in millimetres. AWG matters when you are matching a North American specification or an instrument drawing that was dimensioned that way.
Is the AWG figure a round number for a given millimetre size?
Rarely. The two scales do not line up cleanly: a nominal 0.5 mm conductor sits close to, but not exactly at, a standard AWG size. Enter the millimetre diameter you actually need and the converter gives the fractional gauge, treat a near-miss as a near-miss rather than rounding it to the nearest number.
Does the cross-section tell me the current rating?
No. For thermocouple wire the cross-section matters for series resistance and mechanical life, not for carrying current. A thermocouple loop runs on millivolts at negligible current, which is why the resistance and attenuation figures on this site matter more than any current-carrying rating.
Crossing a metric and imperial specification?
Tell us the gauge or the millimetre diameter your drawing calls for, we confirm the metric equivalent we draw and supply to.