AWG Size Calculator
Choose whether you know the AWG number, the diameter or the area, and enter it. The calculator gives the wire gauge with its diameter, area, resistance and current rating.
- Wire gauge
- Diameter
- Ampacity
For 1/0 to 4/0 AWG, enter 0, −1, −2 or −3.
Each AWG step changes the area by about 26%. 12 AWG copper is 2.05 mm across and 3.31 mm². It carries 25 A at 75 °C, but building codes limit it to a 20 A breaker. Every three gauges halves or doubles the area.
AWG wire size chart
Copper, solid. Search for a gauge.
| AWG | Diameter (mm) | Area (mm²) | Ω per km | Ampacity 75 °C (A) |
|---|---|---|---|---|
| 24 | 0.511 | 0.2 | 84.21 | – |
| 22 | 0.644 | 0.33 | 52.96 | – |
| 20 | 0.812 | 0.52 | 33.31 | – |
| 18 | 1.024 | 0.82 | 20.95 | – |
| 16 | 1.291 | 1.31 | 13.17 | – |
| 14 | 1.628 | 2.08 | 8.28 | 20 |
| 12 | 2.053 | 3.31 | 5.21 | 25 |
| 10 | 2.588 | 5.26 | 3.28 | 35 |
| 8 | 3.264 | 8.37 | 2.06 | 50 |
| 6 | 4.115 | 13.3 | 1.3 | 65 |
| 4 | 5.189 | 21.15 | 0.82 | 85 |
| 2 | 6.544 | 33.63 | 0.51 | 115 |
| 1 | 7.348 | 42.41 | 0.41 | 130 |
| 1/0 | 8.251 | 53.48 | 0.32 | 150 |
| 2/0 | 9.266 | 67.43 | 0.26 | 175 |
| 3/0 | 10.405 | 85.03 | 0.2 | 200 |
| 4/0 | 11.684 | 107.22 | 0.16 | 230 |
Millimetres.
Gauge and size
Copper wire. Slide the gauge.
Nearby gauges are drawn to scale.
How AWG works
Number to size. Step through it.
Gauge
n.
A smaller gauge number means a thicker wire.
Thin, medium or heavy gauge
Wire uses. Compare them.
Signal.
Building wire.
Heavy.
Six gauges down doubles the diameter.
Before you buy wire
Wire checks. Tick each item.
Tick each item as you go.
Long runs may need a thicker wire for voltage drop.
What you get
Gauge sizing. Each tile explains one result.
AWG.
mm and in.
mm².
Amps.
Nearest.
Stranded wire of the same AWG is slightly wider than solid wire.
Frequently Asked Questions
No question matches that search.
What is AWG?
American Wire Gauge, the US system of wire sizes.
How thick is twelve gauge wire?
About two point zero five millimetres across.
What size is fourteen gauge wire in square millimetres?
About two point oh eight mm².
How many amps can twelve gauge wire carry?
Twenty five amps at seventy five degrees, limited to a twenty amp breaker in homes.
Is a lower gauge thicker?
Yes. Smaller numbers are thicker wires.
What is ought gauge?
One ought, written one slash zero, is thicker than one gauge.
How do I convert mm² to AWG?
Enter the area and the calculator finds the smallest gauge that is at least that big.
Know your wire
Convert between AWG, millimetres and square millimetres and see what each wire can carry.
More size calculators
Each one has its own calculator, worked examples and answers to common questions.