🔌 Electronics
Wire Gauge Converter
Convert AWG to cross-sectional area, diameter or circular mils. Enter a value, choose the units, then press Convert.
About the Wire Gauge Converter
American Wire Gauge runs backwards: a smaller number is a thicker wire. AWG 10 is 2.59 mm in diameter and 5.26 mm² in area; AWG 20 is 0.812 mm and 0.518 mm². The scale is logarithmic, with each three-gauge step roughly halving the area.
The defining formula is d = 0.127 × 92^((36 − AWG)/39) mm, where 0.127 mm is AWG 36. Cross-sectional area is πd²/4. Circular mils are a US convention: one circular mil is the area of a circle one thousandth of an inch across, so CMA = d² in mils.
How the calculation works
- Diameter (mm) = 0.127 × 92^((36 − AWG) ÷ 39).
- Area (mm²) = π × diameter² ÷ 4.
- 1 circular mil = 0.000506707 mm².
- Each 3 AWG steps roughly doubles or halves the area.
Reference values
| AWG | Diameter (mm) | Area (mm²) | Typical use |
|---|---|---|---|
| 8 | 3.264 | 8.37 | High-current battery cable |
| 10 | 2.588 | 5.26 | Solar and heavy DC |
| 12 | 2.053 | 3.31 | 20 A house circuits |
| 14 | 1.628 | 2.08 | 15 A lighting circuits |
| 18 | 1.024 | 0.823 | Low-voltage wiring |
| 22 | 0.644 | 0.326 | Signal and control |
| 24 | 0.511 | 0.205 | Ethernet / data |
| 30 | 0.255 | 0.051 | Fine electronics |
Worked example: AWG 12 and its neighbours
AWG 12 is 2.053 mm in diameter and 3.31 mm² in area. Three gauges finer, AWG 15, is 1.450 mm and 1.65 mm²—almost exactly half the area. Three gauges thicker, AWG 9, is 2.906 mm and 6.63 mm²—almost exactly double. That logarithmic step is why a small change in AWG number can matter more than it looks.
AWG 12 is often protected at 20 A in a residential branch circuit, but ampacity is not a property of the wire alone. Insulation temperature rating, bundling, conduit fill and ambient temperature all change the safe current. Check the local electrical code and the manufacturer's table before choosing a breaker.
AWG, SWG and metric wire
American Wire Gauge is not the only gauge in use. Standard Wire Gauge, still found in older British equipment, runs the opposite way for some sizes, and metric wire is sold by cross-sectional area in square millimetres. The same nominal number can therefore describe different conductors: 12 AWG is 3.31 mm², while a “12 gauge” in a metric catalogue may mean 4 mm².
When replacing cable, match the cross-sectional area and the insulation rating rather than the gauge number alone. A conductor that is slightly larger is safe for current but may not fit a terminal, and one that is slightly smaller may overheat. The printed markings on the cable sheath are the authority.