Between its neighbours
12 AWG has 59 % more copper than 14 AWG and 37 % less than 10 AWG. Its DC resistance is 1.98 Ω per 1000 ft at 75 °C (aluminum 3.25), and 1000 ft of it carries 19.8 lb of copper.
12 AWG wire: amps, diameter & uses
12 AWG copper is 0.0808" (2.05 mm) across and 3.31 mm², between 2.5 and 4 mm² metric. It is rated 20 / 25 / 30 A at 60 / 75 / 90 °C and takes a 20 A breaker (the 240.4(D) cap). Used for 20 A kitchen, bathroom, laundry and garage receptacle circuits.
01 · 1:1 wire gauge · caliper
12 AWG · bare solid copper
THIS IS:
12 AWG COPPER · 20 A BREAKER · 2.05 MM COPPER
Gauge
12 AWG
bare solid copper
Breaker
20 A
copper, max
Measured
2.05 mm
0.0808"
The gap is 2.05 mm (0.0808"), which reads as 12 AWG bare solid copper. Measure bare copper for the gauge: insulation is far thicker than the metal.
- Meets NEC 2023 Table 310.16 at 75°C — verify with your local AHJ/inspector310.16
- 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 140.08" · 2.032 mm
- IEC 60228
- 4 mm²between 2.5 and 4 mm²
12 AWG at a glance
Size
- Solid diameter
- 0.0808" · 2.05 mm
- Stranded (7)
- 0.092"
- THHN outside
- 0.13"
- Area
- 6,530 cmil · 3.31 mm²
- Metric
- 2.5 – 4 mm²
- SWG nearest
- 14 (2.032 mm)
Amps
- Copper 60/75/90 °C
- 20 / 25 / 30 A
- Aluminum 75 °C
- 20 A
- Max breaker, THHN
- 20 A
- As NM-B cable
- 20 A · yellow
- Ground for it
- 12 AWG
Run & fit
- 120 V at 16 A
- 56 ft at 3 %
- 240 V at 16 A
- 113 ft at 3 %
- THHN in ½" EMT
- 9
- THHN in ¾" EMT
- 16
- Copper weight
- 19.8 lb/1000 ft
12 AWG reference 21 rows
Sort any column, print a shop sheet, download CSV. Click a row to load it in the calculator.
| Actions | ||||
|---|---|---|---|---|
| 90 | 909 | 1818 | ||
| 45 | 454 | 909 | ||
| 18 | 181 | 363 | ||
| 9 | 90 | 181 | ||
| 6 | 60 | 121 | ||
| 4 | 45 | 90 | ||
| 3 | 30 | 60 |
| Actions | |||||||
|---|---|---|---|---|---|---|---|
| 9 | 16 | 26 | 45 | 61 | 101 | ||
| 8 | 15 | 25 | 43 | 59 | 99 | ||
| 6 | 12 | 20 | 37 | 51 | 86 | ||
| 10 | 17 | 29 | 49 | 67 | 109 | ||
| 9 | 16 | 26 | 46 | 62 | 102 | ||
| 9 | 16 | 24 | 38 | 56 | 98 | ||
| 9 | 16 | 26 | 46 | 59 | 97 |
05 / Field guide
12 AWG
the branch-circuit size.
12 AWG copper is 0.0808" (2.05 mm) across and 3.31 mm², between 2.5 and 4 mm² metric. It is rated 20 / 25 / 30 A at 60 / 75 / 90 °C and takes a 20 A breaker (the 240.4(D) cap). Used for 20 A kitchen, bathroom, laundry and garage receptacle circuits.
Circuits it is used for
12 AWG is the usual choice for 20 A kitchen, bathroom, laundry and garage receptacle circuits. As NM-B it comes as 12/2 and 12/3 with a yellow jacket, held to the 60 °C column (20 A). The equipment ground for its largest breaker is 12 AWG.
On the 1:1 gauge
The caliper above opens at 2.05 mm. Lay a stripped length along the lines and step the gauge with ← and → until the wire just fills the gap.
Questions
Answered plainly.
01How many amps can 12 AWG wire carry?
+−
12 AWG copper is rated 20 A at 60 °C, 25 A at 75 °C and 30 A at 90 °C (NEC Table 310.16, 30 °C, three conductors or fewer). 240.4(D) still limits it to a 20 A breaker. Aluminum of the same size: 20 A at 75 °C.
02What size breaker for 12 AWG wire?
+−
Up to 20 A with THHN on 75 °C terminals, 20 A as NM-B cable (60 °C).
03What is the diameter of 12 AWG wire?
+−
0.0808 inch (2.05 mm) solid, 0.092 inch stranded (7 strands), about 0.13 inch with THHN insulation.
04What is 12 AWG in mm²?
+−
3.31 mm² (6,530 circular mils). The IEC sizes either side are 2.5 and 4 mm²; replace it with 4 mm², not the smaller one.
05How far can 12 AWG wire run?
+−
At 16 A and 3 % drop, 56 ft one way at 120 V and 113 ft at 240 V (Table 8 resistance, 1.98 Ω per 1000 ft at 75 °C). Lighter loads go proportionally further.
06How many 12 AWG wires fit in ½" EMT?
+−
9 THHN conductors in ½" EMT, 16 in ¾" and 26 in 1" (NEC Chapter 9, 40 % fill for three or more).
07How far can 12 AWG speaker wire run?
+−
About 125 ft to an 8 Ω speaker and 62 ft to a 4 Ω one before the cable passes 5 % of the impedance (about 0.42 dB).