Calculator KB-52
AWG to mm² and diameter conversion
Wires and Chinese product listings often specify wire gauge in AWG. Convert it here to familiar units.
Result
In brief: Convert American Wire Gauge (AWG) to millimeters and square millimeters and back: diameter, cross-section, copper wire resistance per meter, and approximate current rating. Example: Gauge: AWG 18.
Calculation example
| Known values | AWG number |
|---|---|
| Value | 18 |
| Gauge | AWG 18 |
|---|---|
| Diameter | 1.024 mm |
| Wire gauge | 0.823 mm² |
| Copper resistance | 21.3 mΩ/m |
| Current in a short length | 4.9 A |
| Current in a bundle or cable | 2.5 A |
How it is calculated
S = π · d² / 4
The higher the AWG number, the thinner the wire: every 6 gauge numbers halve the diameter, and every 3 halve the cross-section. The current ratings are rough guidelines based on current densities of 6 and 3 A/mm². In practice, they depend on insulation and cooling.
What to look for
- Cheap cables are often thinner than their stated AWG. For stranded wire, check the resistance per meter.
- For precise sizing based on current and voltage drop, use the separate wire gauge calculator.
Frequently asked questions
How many mm² is 18 AWG?
0.823 mm², 1.024 mm diameter, with copper resistance of about 21.3 mΩ per meter.
What AWG size corresponds to 2.5 mm²?
About 13 AWG (2.63 mm²). 1.5 mm² falls between 15 and 16 AWG, while 1 mm² is close to 17 AWG.
How does the AWG scale work?
The higher the number, the thinner the wire: every 3 gauge numbers halve the cross-sectional area, and every 6 numbers halve the diameter. The allowable current also depends on the insulation and cooling.
