Wire Gauge Chart
American Wire Gauge (AWG) sizes from 4/0 down to 40, with each wire's diameter, cross-sectional area, copper resistance, and allowable current. Use the converters to go from a gauge to millimeters, or from a measured diameter back to the nearest gauge.
AWG to mm
- Diameter
- 2.053 mm
- Diameter
- 0.0808 in
- Area
- 3.31 mm²
- Area
- 6.53 kcmil
- Copper resistance
- 1.588 Ω / 1000 ft
- NEC amps (60/75/90 °C)
- 20 / 25 / 30 A
Diameter to AWG
Closest standard size
12 AWG
2.000 mm (0.0787 in) works out to 12.22 on the AWG scale.
Stranded wire measures slightly larger than solid wire of the same gauge, so measure a single strand or strip a solid conductor for an accurate reading.
AWG wire size chart
| AWG | Dia. (in) | Dia. (mm) | Area (mm²) | Area (kcmil) | Ω / 1000 ft | Ω / km | Amps 60 / 75 / 90 °C |
|---|---|---|---|---|---|---|---|
| 4/0 | 0.4600 | 11.684 | 107 | 212 | 0.04901 | 0.1608 | 195 / 230 / 260 |
| 3/0 | 0.4096 | 10.405 | 85.0 | 168 | 0.0618 | 0.2028 | 165 / 200 / 225 |
| 2/0 | 0.3648 | 9.266 | 67.4 | 133 | 0.07793 | 0.2557 | 145 / 175 / 195 |
| 1/0 | 0.3249 | 8.251 | 53.5 | 106 | 0.09827 | 0.3224 | 125 / 150 / 170 |
| 1 | 0.2893 | 7.348 | 42.4 | 83.7 | 0.1239 | 0.4066 | 110 / 130 / 145 |
| 2 | 0.2576 | 6.544 | 33.6 | 66.4 | 0.1563 | 0.5127 | 95 / 115 / 130 |
| 3 | 0.2294 | 5.827 | 26.7 | 52.6 | 0.197 | 0.6465 | 85 / 100 / 115 |
| 4 | 0.2043 | 5.189 | 21.2 | 41.7 | 0.2485 | 0.8152 | 70 / 85 / 95 |
| 5 | 0.1819 | 4.621 | 16.8 | 33.1 | 0.3133 | 1.028 | — |
| 6 | 0.1620 | 4.115 | 13.3 | 26.3 | 0.3951 | 1.296 | 55 / 65 / 75 |
| 7 | 0.1443 | 3.665 | 10.5 | 20.8 | 0.4982 | 1.634 | — |
| 8 | 0.1285 | 3.264 | 8.37 | 16.5 | 0.6282 | 2.061 | 40 / 50 / 55 |
| 9 | 0.1144 | 2.906 | 6.63 | 13.1 | 0.7921 | 2.599 | — |
| 10 | 0.1019 | 2.588 | 5.26 | 10.4 | 0.9989 | 3.277 | 30 / 35 / 40 |
| 11 | 0.0907 | 2.305 | 4.17 | 8.23 | 1.26 | 4.132 | — |
| 12 | 0.0808 | 2.053 | 3.31 | 6.53 | 1.588 | 5.211 | 20 / 25 / 30 |
| 13 | 0.0720 | 1.828 | 2.62 | 5.18 | 2.003 | 6.571 | — |
| 14 | 0.0641 | 1.628 | 2.08 | 4.11 | 2.525 | 8.286 | 15 / 20 / 25 |
| 15 | 0.0571 | 1.450 | 1.65 | 3.26 | 3.184 | 10.45 | — |
| 16 | 0.0508 | 1.291 | 1.31 | 2.58 | 4.016 | 13.17 | — |
| 17 | 0.0453 | 1.150 | 1.04 | 2.05 | 5.064 | 16.61 | — |
| 18 | 0.0403 | 1.024 | 0.823 | 1.62 | 6.385 | 20.95 | — |
| 19 | 0.0359 | 0.912 | 0.653 | 1.29 | 8.051 | 26.42 | — |
| 20 | 0.0320 | 0.812 | 0.518 | 1.02 | 10.15 | 33.31 | — |
| 21 | 0.0285 | 0.723 | 0.410 | 0.810 | 12.8 | 42 | — |
| 22 | 0.0253 | 0.644 | 0.326 | 0.642 | 16.14 | 52.96 | — |
| 23 | 0.0226 | 0.573 | 0.258 | 0.509 | 20.36 | 66.79 | — |
| 24 | 0.0201 | 0.511 | 0.205 | 0.404 | 25.67 | 84.22 | — |
| 25 | 0.0179 | 0.455 | 0.162 | 0.320 | 32.37 | 106.2 | — |
| 26 | 0.0159 | 0.405 | 0.129 | 0.254 | 40.81 | 133.9 | — |
| 27 | 0.0142 | 0.361 | 0.102 | 0.202 | 51.47 | 168.9 | — |
| 28 | 0.0126 | 0.321 | 0.0810 | 0.160 | 64.9 | 212.9 | — |
| 29 | 0.0113 | 0.286 | 0.0642 | 0.127 | 81.84 | 268.5 | — |
| 30 | 0.0100 | 0.255 | 0.0509 | 0.101 | 103.2 | 338.6 | — |
| 31 | 0.0089 | 0.227 | 0.0404 | 0.0797 | 130.1 | 426.9 | — |
| 32 | 0.0080 | 0.202 | 0.0320 | 0.0632 | 164.1 | 538.3 | — |
| 33 | 0.0071 | 0.180 | 0.0254 | 0.0501 | 206.9 | 678.8 | — |
| 34 | 0.0063 | 0.160 | 0.0201 | 0.0398 | 260.9 | 856 | — |
| 35 | 0.0056 | 0.143 | 0.0160 | 0.0315 | 329 | 1079 | — |
| 36 | 0.0050 | 0.127 | 0.0127 | 0.0250 | 414.8 | 1361 | — |
| 37 | 0.0045 | 0.113 | 0.0100 | 0.0198 | 523.1 | 1716 | — |
| 38 | 0.0040 | 0.101 | 0.00797 | 0.0157 | 659.6 | 2164 | — |
| 39 | 0.0035 | 0.090 | 0.00632 | 0.0125 | 831.8 | 2729 | — |
| 40 | 0.0031 | 0.080 | 0.00501 | 0.00989 | 1049 | 3441 | — |
Ampacity is shown only for the sizes listed in NEC Table 310.16 (14 AWG and larger; the table skips 5, 7, 9, 11, and 13). For 14, 12, and 10 AWG the NEC also caps the breaker at 15, 20, and 30 A. Aluminum values and derating for heat and bundled wires are on the ampacity chart.
Common household wire sizes
| Copper wire | Max breaker | Typical use |
|---|---|---|
| 14 AWG | 15 A | Lighting and general outlets on 15 A circuits |
| 12 AWG | 20 A | Kitchen, bathroom, laundry, and garage outlets |
| 10 AWG | 30 A | Electric water heaters, many electric dryers |
Always follow the appliance's nameplate and local code; larger loads such as ranges and EV chargers need sizing by an electrician.
Wire Gauge Chart FAQ
What wire gauge do I need for 15, 20, and 30 amp circuits?
For standard copper house wiring, the NEC limits overcurrent protection to 15 A for 14 AWG, 20 A for 12 AWG, and 30 A for 10 AWG. So a 15 A circuit uses 14 AWG, a 20 A circuit 12 AWG, and a 30 A circuit 10 AWG. Long runs may need a larger wire to limit voltage drop.
Is a higher gauge number thicker or thinner?
Thinner. AWG numbers go up as wire gets smaller: 10 AWG is thicker than 14 AWG. Sizes larger than 1 AWG are written 1/0, 2/0, 3/0, and 4/0 (also 0, 00, 000, 0000).
How thick is 12 gauge wire?
Solid 12 AWG wire is 0.0808 in (2.053 mm) in diameter with a cross-section of 3.31 mm². Stranded 12 AWG has the same copper area but measures slightly larger overall.
What does the 60/75/90 °C ampacity mean?
It is the insulation's temperature rating. NM-B cable (Romex) is limited to the 60 °C column; THWN conductors use 75 °C; THHN and XHHW-2 are rated 90 °C. Terminals on breakers and devices are often rated only 60 or 75 °C, which can cap the usable ampacity.
Sources
Diameters and areas come from the AWG definition in ASTM B258: d = 0.005 in × 92(36 − n)/39. Copper resistance (solid wire, 20 °C) is from Wikipedia's “American wire gauge” table. Ampacity is NEC Table 310.16 (copper, 30 °C ambient, up to three current-carrying conductors), checked against Cerrowire's chart.
Ampacity needs correction for ambient temperature, bundling, and terminal ratings. Have a licensed electrician confirm wire sizes for any real installation.