Wire AWG Size Conversion Calculator
CE Style
Converted Size
Nearby Gauges
| AWG | Diameter (mm) | Area (mm²) | cmil | R (Ω/m) Cu @T | R (Ω/1000 ft) Cu @T |
|---|
How to Use the AWG Size Conversion Calculator
Convert between AWG, diameter, area, circular mils, and temperature-adjusted copper resistance. Use this to match wire tables, compare sizes, and pick nearby gauges.
1) Choose Mode
- AWG → Size: pick a gauge and the tool fills diameter, area, cmil, and resistance.
- Size → AWG: enter diameter or area and the tool rounds to the nearest nominal AWG.
2) Enter AWG or Size
- AWG: includes 1/0, 2/0, 3/0, 4/0.
- Diameter: round-wire equivalent (mm or inch).
- Area: conductor cross-section (mm² / cmil / kcmil). cmil = mils².
Stranded wire has slightly larger outside diameter than solid for the same area; conversions use conductor area, not overall OD with insulation.
3) Units & Ambient
- Pick preferred units for diameter and area.
- Set Ambient (°C) to update copper resistance using
ρ(T)=ρ₍20°C₎·(1+α·(T−20)).
4) Read Converted Size
- Diameter (mm/in) and Area (mm², cmil, kcmil).
- Resistance of copper at ambient in Ω/m and Ω/1000 ft (for quick drop estimates).
AWG diameter uses the standard relation:
d(mm)=0.127·92^((36−n)/39), area = π(d/2)².5) Nearby Gauges
- Table shows ±5 gauges around the current selection with diameter, area, cmil, and copper resistance.
- Use it to pick the next larger/smaller size without leaving the page.
Quick Checklist
- Correct mode selected (AWG→Size or Size→AWG)
- Units set as needed (mm/in, mm²/cmil/kcmil)
- Ambient realistic for your application
- Remember: area is conductor cross-section, not OD with insulation
- For stranded, check manufacturer datasheet for exact OD
- Use nearby table to choose standard AWG numbers
FAQ & Tips
Why doesn’t OD match my cable?
Overall diameter includes insulation and strand lay. This tool converts the conductor only.
Metric sizes vs AWG?
Many metric cables are specified by mm²; use Size → AWG to find the nearest gauge for connectors or terminals.
What is cmil?
Circular mils = (diameter in mils)2. 1 kcmil = 1000 cmil.
Temperature and resistance?
Hotter copper has higher resistivity. Set Ambient to get Ω/m and Ω/1000 ft at temperature.
Copy-Paste Mini Workflow
1) Pick mode: AWG → Size or Size → AWG
2) Enter AWG or enter Diameter/Area with units
3) Set Ambient (°C) to get resistance at temperature
4) Read converted size + resistance
5) Use Nearby Gauges to pick the closest standard size