Between its neighbours
20 AWG has 59 % more copper than 22 AWG and 37 % less than 18 AWG. Its DC resistance is 12.341 Ω per 1000 ft at 75 °C, and 1000 ft of it carries 3.09 lb of copper.
20 AWG wire: amps, diameter & uses
20 AWG wire is 0.0320" across, 0.812 mm, about 31 turns per inch wound tight. Ten turns measure 8.12 mm, the reliable way to check it; the nearest British size is SWG 21 (0.813 mm). Its copper resistance is 10.1 Ω per 1000 ft at 20 °C. Used for hook-up wire, LED strips and 12 V signal runs.
01 · 1:1 wire gauge · coil wrap
20 AWG · bare solid copper
THIS IS:
20 AWG COPPER · NOT BUILDING WIRE · 0.81 MM COPPER
Gauge
20 AWG
bare solid copper
Breaker
n/a
not building wire
Measured
0.810 mm
0.0319"
10 turns over 8.10 mm is 0.810 mm per turn: 20 AWG (0.812 mm), SWG 21.
- Drawn at true sizecalibrated screen
20 AWG
- Solid diameter
- 0.0320"0.812 mm · ASTM B258 formula
- Area
- 1,022 cmil0.518 mm² · nearest IEC 0.5 mm²
- DC resistance, 75 °C
- 12.341 Ω/1000 ftcopper, from resistivity
- Copper weight
- 3.09 lb/1000 ft
Ampacity
- Table 310.16
- not listedsmaller than building wire: see the chassis and craft notes
Other gauges
- Nearest SWG
- SWG 210.032" · 0.813 mm
- IEC 60228
- 0.5 mm²between 0.5 and 0.75 mm²
20 AWG at a glance
Size
- Solid diameter
- 0.0320" · 0.812 mm
- Area
- 1,022 cmil · 0.518 mm²
- Metric
- 0.5 – 0.75 mm²
- SWG nearest
- 21 (0.813 mm)
Electrical
- Resistance 20 °C
- 10.15 Ω/1000 ft
- Resistance 75 °C
- 12.341 Ω/1000 ft
- As cord
- not rated
- Copper weight
- 3.09 lb/1000 ft
Measure & run
- 10 turns measure
- 8.12 mm
- Turns per inch
- 31.3
- 12 V at 1 A
- 14 ft at 3 %
20 AWG reference 20 rows
Sort any column, print a shop sheet, download CSV. Click a row to load it in the calculator.
| Actions | ||||
|---|---|---|---|---|
| 14 | 145 | 291 | ||
| 7 | 72 | 145 | ||
| 2 | 29 | 58 | ||
| 1 | 14 | 29 | ||
| 0 | 9 | 19 | ||
| 0 | 7 | 14 | ||
| 0 | 4 | 9 | ||
| 0 | 3 | 7 | ||
| 0 | 2 | 4 | ||
| 0 | 1 | 3 | ||
| 0 | 1 | 2 | ||
| 0 | 0 | 1 | ||
| 0 | 0 | 1 |
05 / Field guide
20 AWG
measured by the coil.
20 AWG wire is 0.0320" across, 0.812 mm, about 31 turns per inch wound tight. Ten turns measure 8.12 mm, the reliable way to check it; the nearest British size is SWG 21 (0.813 mm). Its copper resistance is 10.1 Ω per 1000 ft at 20 °C. Used for hook-up wire, LED strips and 12 V signal runs.
Electronics and craft
20 AWG is used for hook-up wire, LED strips and 12 V signal runs. At 31 turns to the inch it is fine enough that a single pixel on most screens is 25 % of its width.
On the 1:1 gauge
The caliper above opens at 0.812 mm. Lay a stripped length along the lines and step the gauge with ← and → until the wire just fills the gap.
Questions
Answered plainly.
01How many amps can 20 AWG wire carry?
+−
Table 310.16 does not rate it: 20 AWG is electronics, signal and craft wire. In practice it carries well under 1 A in bundles; check the maker’s rating.
02What is the diameter of 20 AWG wire?
+−
0.0320 inch (0.812 mm) solid.
03What is 20 AWG in mm²?
+−
0.518 mm² (1,022 circular mils). The IEC sizes either side are 0.5 and 0.75 mm²; replace it with 0.75 mm², not the smaller one.
04How do I measure 20 AWG wire?
+−
Wind 10 tight turns side by side and measure the coil: 8.12 mm for 20 AWG. A ruler or a screen cannot resolve a single strand this fine.
05What is 20 AWG in SWG?
+−
The nearest British Standard Wire Gauge is SWG 21 at 0.813 mm, against 0.812 mm for 20 AWG.