WIRE GAUGE CHARTS
21 wire in mm
Thickness: 0.72 mm diameter (0.028 inches), 0.41 mm² cross-section of solid copper.
Specifications
- Diameter
- 0.72 mm
- Diameter (imperial)
- 0.028 in
- Cross-section
- 0.41 mm²
- Area (kcmil)
- 0.8
- Copper resistance
- 12.802 Ω/1000 ft
- Copper resistance (metric)
- 42.00 Ω/km
- Copper weight
- 3.7 g/m
- Free-air rating (typical)
- 25 A
Nearest metric sizes
0.41 mm² does not match a standard metric cable size exactly. The closest conventional cross-sections are0.5 mm², 0.75 mm² and 1 mm²— engineers round this wire up (larger cross-section) for ampacity, or accept the raw equality for signal work.
One gauge away:22 · thinner20 · thickerFull chart →
Frequently asked questions
Is 21 gauge wire thick or thin?
21 gauge wire is 0.72 mm in diameter. On the AWG scale a lower number means a thicker wire, so 21 AWG sits near the thin end of the chart.
What diameter is 21 wire in millimeters?
21 gauge wire is 0.72 mm (0.028 in) in diameter, with a solid-conductor cross-section of 0.41 mm².