From AWG to mm²
The area in mm² is the circular mils × 0.0005067. 14 AWG is 2.08 mm² (between 1.5 and 2.5), 12 AWG 3.31 mm² (between 2.5 and 4), 10 AWG 5.26 mm², nearest 6 mm².
mm² = cmil × 0.0005067 diameter (mm) = √(4 × mm² ÷ π)
AWG to mm & mm² conversion chart
AWG to mm² and mm chart with solid and stranded diameters and the IEC 60228 metric size each one sits between. 12 AWG is 3.31 mm² (2.05 mm across), between 2.5 and 4 mm². 14 AWG is 2.08 mm²; use the next metric size up, never down.
01 · 1:1 wire gauge · caliper
2.5 mm² · IEC 60228 metric
THIS IS:
2.5 MM² · ≈ 14 AWG
Metric
2.5 mm²
1.78 mm solid
Nearest AWG
14 AWG
Class 2 max
7.41 Ω/km
class 5: 7.98
The gap is 1.78 mm (0.0702"), which reads as 14 AWG IEC 60228 metric (+9.6 %). Measure bare copper for the gauge: insulation is far thicker than the metal.
- Drawn at true sizecalibrated screen
12 AWG
- Solid diameter
- 0.0808"2.053 mm · ASTM B258 formula
- Stranded (7 strands)
- 0.0920"2.337 mm · Table 8
- THHN outside
- 0.130"3.30 mm · 0.0133 in² · Table 5
- Area
- 6,530 cmil3.31 mm² · nearest IEC 4 mm²
- DC resistance, 75 °C
- 1.98 Ω/1000 ftaluminum 3.25 Ω/1000 ft · Table 8
- Copper weight
- 19.8 lb/1000 ft
Ampacity
- Copper 60 / 75 / 90 °C
- 20 / 25 / 30 ANM-B uses the 60 °C column (334.80)
- Aluminum 60 / 75 / 90 °C
- 15 / 20 / 25 A
- Largest breaker (Cu, 75 °C)
- 20 A240.4(D) small-conductor cap
Other gauges
- Nearest SWG
- SWG 150.072" · 1.829 mm
- IEC 60228
- 4 mm²between 2.5 and 4 mm²
AWG and metric tables 88 rows
Sort any column, print a shop sheet, download CSV. Click a row to load it in the calculator.
| Actions | ||||||
|---|---|---|---|---|---|---|
| 0.80 | 20 AWG | 20 AWG | 36 | 39 | ||
| 0.98 | 18 AWG | 18 AWG | 24.5 | 26 | ||
| 1.13 | 18 AWG | 16 AWG | 18.1 | 19.5 | ||
| 1.38 | 16 AWG | 14 AWG | 12.1 | 13.3 | ||
| 1.78 | 14 AWG | 12 AWG | 7.41 | 7.98 | ||
| 2.26 | 12 AWG | 10 AWG | 4.61 | 4.95 | ||
| 2.76 | 10 AWG | 8 AWG | 3.08 | 3.3 | ||
| 3.57 | 8 AWG | 6 AWG | 1.83 | 1.91 | ||
| 4.51 | 6 AWG | 4 AWG | 1.15 | 1.21 | ||
| 5.64 | 3 AWG | 3 AWG | 0.727 | 0.78 | ||
| 6.68 | 2 AWG | 1 AWG | 0.524 | 0.554 | ||
| 7.98 | 1/0 AWG | 1/0 AWG | 0.387 | 0.386 | ||
| 9.44 | 2/0 AWG | 3/0 AWG | 0.268 | 0.272 | ||
| 11.00 | 3/0 AWG | 4/0 AWG | 0.193 | 0.206 | ||
| 12.36 | 250 kcmil | 250 kcmil | 0.153 | 0.161 | ||
| 13.82 | 300 kcmil | 300 kcmil | 0.124 | 0.129 | ||
| 15.35 | 350 kcmil | 400 kcmil | 0.0991 | 0.106 | ||
| 17.48 | 500 kcmil | 500 kcmil | 0.0754 | 0.0801 |
Class 2 is stranded building wire, class 5 is flexible cord. Never substitute a smaller metric size for an AWG size in a US installation.
Solid diameters from the AWG formula (ASTM B258); stranding, stranded diameters and resistance from NEC Chapter 9 Table 8; ampacity from Table 310.16 (NEC 2023), 30 °C ambient, not more than three current-carrying conductors.
| 7/0 | 0.5 | 12.7 | 4/0 AWG |
|---|---|---|---|
| 6/0 | 0.464 | 11.786 | 4/0 AWG |
| 5/0 | 0.432 | 10.973 | 3/0 AWG |
| 4/0 | 0.4 | 10.16 | 3/0 AWG |
| 3/0 | 0.372 | 9.449 | 2/0 AWG |
| 2/0 | 0.348 | 8.839 | 2/0 AWG |
| 0 | 0.324 | 8.23 | 1/0 AWG |
| 1 | 0.3 | 7.62 | 1 AWG |
| 2 | 0.276 | 7.01 | 1 AWG |
| 3 | 0.252 | 6.401 | 2 AWG |
| 4 | 0.232 | 5.893 | 3 AWG |
| 5 | 0.212 | 5.385 | 4 AWG |
| 6 | 0.192 | 4.877 | 4 AWG |
| 7 | 0.176 | 4.47 | 6 AWG |
| 8 | 0.16 | 4.064 | 6 AWG |
| 9 | 0.144 | 3.658 | 8 AWG |
| 10 | 0.128 | 3.251 | 8 AWG |
| 11 | 0.116 | 2.946 | 8 AWG |
| 12 | 0.104 | 2.642 | 10 AWG |
| 13 | 0.092 | 2.337 | 10 AWG |
| 14 | 0.08 | 2.032 | 12 AWG |
| 15 | 0.072 | 1.829 | 14 AWG |
| 16 | 0.064 | 1.626 | 14 AWG |
| 17 | 0.056 | 1.422 | 16 AWG |
| 18 | 0.048 | 1.219 | 16 AWG |
| 19 | 0.04 | 1.016 | 18 AWG |
| 20 | 0.036 | 0.914 | 20 AWG |
| 21 | 0.032 | 0.813 | 20 AWG |
| 22 | 0.028 | 0.711 | 22 AWG |
| 23 | 0.024 | 0.61 | 22 AWG |
| 24 | 0.022 | 0.559 | 24 AWG |
| 25 | 0.02 | 0.508 | 24 AWG |
| 26 | 0.018 | 0.4572 | 26 AWG |
| 27 | 0.0164 | 0.4166 | 26 AWG |
| 28 | 0.0148 | 0.3759 | 26 AWG |
| 29 | 0.0136 | 0.3454 | 28 AWG |
| 30 | 0.0124 | 0.315 | 28 AWG |
| 31 | 0.0116 | 0.2946 | 28 AWG |
| 32 | 0.0108 | 0.2743 | 30 AWG |
| 33 | 0.01 | 0.254 | 30 AWG |
| 34 | 0.0092 | 0.2337 | 30 AWG |
| 35 | 0.0084 | 0.2134 | 32 AWG |
| 36 | 0.0076 | 0.193 | 32 AWG |
| 37 | 0.0068 | 0.1727 | 34 AWG |
| 38 | 0.006 | 0.1524 | 34 AWG |
| 39 | 0.0052 | 0.1321 | 36 AWG |
| 40 | 0.0048 | 0.1219 | 36 AWG |
05 / Field guide
Area, not
a number.
Outside North America wire is sold by cross-section in square millimetres (IEC 60228): 1.5, 2.5, 4, 6, 10 mm² and so on. AWG sizes fall between them, so a conversion always names the metric sizes on either side. When an AWG size is specified, use the metric size at least as large, never the nearest smaller one.
Solid, stranded, class 2, class 5
IEC 60228 class 2 is stranded building wire, class 5 is flexible cord; the standard sets their maximum resistance, not their diameter. US stranded wire (ASTM B8 class B) is larger across than solid of the same gauge because of the gaps between strands.
Why the screen can be trusted
A browser does not know how big its pixels are, so the gauge starts from a table of 114 phones, tablets, laptops and monitors matched to your screen’s size and pixel ratio, an estimate good to about five percent. Laying a coin or a bank card on the glass and matching its outline replaces the estimate with a measurement good to a fraction of a percent, saved for this screen only.
Browser zoom is corrected automatically from the pixel ratio; pinch zoom is flagged, because nothing drawn is true size until it is undone.
pixels per mm = CSS px across the card ÷ 85.60 mm ID-1 card: 85.60 × 53.98 mm (ISO/IEC 7810)
Colours and insulation differ too
IEC-harmonised cable uses brown for the line, blue for the neutral and green-yellow for protective earth; North American wiring uses black or red for the hot, white for the neutral and green or bare copper for the ground. Insulation thickness differs as well, so a metric cable and an AWG cable of similar copper can have different outside diameters.
When a design specifies AWG, choose the metric size at least as large: 14 AWG becomes 2.5 mm², 12 AWG becomes 4 mm², 10 AWG becomes 6 mm². 5.26 mm² of 10 AWG is between 4 and 6 mm², so 4 mm² would be undersized.
Questions
Answered plainly.
01What is 12 AWG in mm²?
+−
3.31 mm². The nearest IEC sizes are 2.5 mm² (smaller) and 4 mm² (larger); replace 12 AWG with 4 mm².
02What is 2.5 mm² in AWG?
+−
Between 14 AWG (2.08 mm²) and 12 AWG (3.31 mm²); it is closest to 13 AWG, a size rarely sold. Treat it as 14 AWG for ampacity.
03How do I convert AWG diameter to mm?
+−
Multiply the inches by 25.4: 12 AWG is 0.0808 in, 2.05 mm. The table gives solid and stranded diameters for every size.
04Is 1.5 mm² the same as 16 AWG?
+−
16 AWG is 1.31 mm², smaller than 1.5 mm²; 1.5 mm² sits between 16 and 14 AWG.
05What is SWG?
+−
The British Standard Wire Gauge, a different scale used in older British practice and in some craft wire. SWG 16 is 1.626 mm, close to 14 AWG (1.628 mm); at other numbers the two differ.
06What is 6 mm² in AWG?
+−
6 mm² is close to 10 AWG (5.26 mm²) but larger; it is slightly smaller than 9 AWG. Use it where 10 AWG is specified.
07Why does metric cable look thicker?
+−
Insulation and sheath thickness follow different standards, and IEC flexible cords are often class 5 fine-stranded. Compare the copper area in mm², not the outside diameter.