24 AWG wire size
0.511 mm · 0.205 mm²
0.0201 in diameter · 84.208 Ω/km in copper
What 24 AWG is used for
Ethernet and telephone pairs, ribbon cable, most hookup wire.
The numbers
| Diameter | 0.511 mm · 0.0201 in |
| Cross-sectional area | 0.2047 mm² |
| Resistance, copper | 84.208 Ω/km · 25.667 Ω per 1,000 ft |
| Resistance, aluminium | 137.742 Ω/km |
| NEC 60 °C copper ampacity | — outside the common building-wire range |
How 24 compares
The gauge scale is geometric, so the useful comparisons are ratios rather than differences. 18 AWG is twice the diameter, which is four times the area.
| Gauge | Diameter | Area | Ω/km copper | vs 24 |
|---|---|---|---|---|
| 18 | 1.024 mm | 0.823 mm² | 20.95 | 4.02× the area |
| 20 | 0.812 mm | 0.518 mm² | 33.31 | 2.53× the area |
| 22 | 0.644 mm | 0.326 mm² | 52.96 | 1.59× the area |
| 26 | 0.405 mm | 0.129 mm² | 133.9 | 0.63× the area |
| 28 | 0.321 mm | 0.081 mm² | 212.9 | 0.4× the area |
| 30 | 0.255 mm | 0.051 mm² | 338.53 | 0.25× the area |
Frequently asked questions
What is 24 AWG in mm?
0.511 mm in diameter (0.0201 inches), with a cross-sectional area of 0.205 mm².
Is 24 AWG used for power wiring?
Not for building circuits. It is a signal and low-current gauge — thinner than anything a domestic branch circuit uses.
What is the resistance of 24 AWG copper?
84.208 Ω per kilometre, or 25.667 Ω per 1,000 feet, for annealed copper at 20 °C. The same gauge in aluminium is about 137.74 Ω/km — 1.64 times higher, which is why aluminium wiring is sized larger for the same load.
Why do smaller AWG numbers mean thicker wire?
The number counts drawing operations. Wire is pulled through progressively smaller dies, and the gauge records how many passes it took — so more passes means a higher number and a thinner wire.