Electronics & Wiring
20 AWG wire size (0.812 mm → 0.03196 in)
Reference dimensions for 20 AWG: nominal diameter in millimeters and inches, cross-sectional area, and circular mils (CM/kcmil). Use the links below to compare nearby gauges and open the full AWG chart.
Dimensions
AWG reference values for solid conductor baseline.
- Gauge: 20 AWG
- Diameter: 0.812 mm (0.03196 in)
- Area: 0.5176 mm²
- Circular mils: 1021.5 CM (1.022 kcmil)
- Formula: diameter = 0.005 × 92^((36 − AWG)/39); mm = in × 25.4
Based on nominal solid conductor diameter. Stranded diameters vary. Resistance uses copper resistivity ≈ 1.724 µΩ·cm at 20°C.
References: IACS 100% copper resistivity and IEC 60228 conductor classes (informational). For ampacity, consult NEC/IEC tables and manufacturer datasheets.
Use with confidence
For stranded wire, overall diameter varies with strand count and insulation. Check datasheets for exact OD and ampacity, and reference the full AWG chart for neighboring gauges.
Compare neighboring gauges
FAQ
What is the diameter of 20 AWG wire?
20 AWG has a nominal diameter of 0.812 mm (0.03196 in). Values are calculated with the standard AWG formula (0.005 × 92^((36 − AWG)/39)).
What is the cross-sectional area of 20 AWG?
The area is 0.5176 mm², equivalent to 1021.5 circular mils (1.022 kcmil). Always verify stranded diameters and insulation from manufacturer data.
Is 20 AWG diameter the same for solid and stranded?
No. AWG denotes conductor cross-sectional area, not overall OD. Stranded conductors may have slightly different overall diameters due to lay and compaction, and insulation thickness further changes OD. Check the datasheet for exact OD.
What is the copper DC resistance of 20 AWG at 20°C?
Approx. 33.31 Ω/km for copper at 20°C. Resistance increases with temperature (~0.393% per °C) and varies by alloy and construction. Use manufacturer data for precise values.
Does insulation change the AWG size?
AWG describes the conductor only. Insulation and jackets increase the overall outer diameter (OD). Always reference OD and insulation type (e.g., PVC, XLPE, PTFE) when routing or selecting connectors.
How do you convert 20 AWG to mm and inches?
Use the AWG diameter formula: 0.005 × 92^((36 − AWG)/39) to get inches. Then convert to millimeters with mm = in × 25.4.
What are circular mils (CM) and kcmil for 20 AWG?
1021.5 CM (1.022 kcmil). Circular mils are (in × 1000)^2; kcmil = CM ÷ 1000. These units are common in North American ampacity tables.
Is ampacity determined only by AWG?
No. Ampacity depends on insulation rating, ambient temperature, bundling, installation method, and applicable code (NEC/IEC). Use manufacturer tables and standards—do not rely on AWG alone.
How should I measure wire diameter?
Use calipers or micrometers. For stranded wire, measure overall conductor diameter or individual strand diameters and compute the equivalent area. Compaction and lay affect readings.
Are these values nominal or exact?
Nominal. Actual dimensions vary with tolerance, strand count, and insulation. Verify the exact product dimensions using the manufacturer datasheet.
Where can I compare 20 AWG to other gauges?
Use the full AWG chart to compare 20 AWG with neighboring gauges, convert to mm or inches, and review notes on stranded vs solid wire and ampacity considerations.
Need the full AWG table?
View the complete AWG to mm and inches chart for solid and stranded references, or switch back to the mm to inches calculator for arbitrary values.