Conversion GuidesIntermediate
AWG to mm²: Wire Gauge Conversion Table and Guide
Convert American Wire Gauge (AWG) to Metric (mm²). Understand why AWG numbers get smaller as wires get larger and how to choose the right wire size.
EngConvert TeamFebruary 9, 20263 min read
AWG to mm²: Wire Gauge Conversion Table and Guide
If you work with electronics or home wiring, you will encounter two incompatible systems: AWG (American Wire Gauge) and Metric (mm²). Buying the wrong wire can lead to fires or voltage drops. This guide sorts it out.
Quick Answer (TL;DR)
- The Rule: In AWG, smaller number = thicker wire. (Reverse scale).
- The Metric: Directly measures cross-sectional area in square millimeters (mm²).
Key Equivalents:
- 18 AWG ≈ 0.75 mm² (Lamp cord)
- 14 AWG ≈ 2.5 mm² (Home household circuit)
- 10 AWG ≈ 6.0 mm² (Dryer/AC)
- 4/0 AWG is huge; 30 AWG is hair-thin.
Why is AWG "Backwards"?
AWG represents the number of times a wire was drawn through a die to thin it out.
- 0 AWG: Drawn 0 times (Thick).
- 30 AWG: Drawn through sizing dies 30 times (Very thin).
AWG to mm² Conversion Chart
| AWG Size | CSA (mm²) | Nearest Metric Standard | Common Use | Max Amps (Approx) |
|---|---|---|---|---|
| 30 | 0.05 | - | PCB jumper wires | 0.5A |
| 24 | 0.20 | 0.25 mm² | Ethernet (Cat5/6) | 2A |
| 22 | 0.32 | 0.35 mm² | LED strip signals | 5A |
| 20 | 0.52 | 0.50 mm² | Small electronics | 6A |
| 18 | 0.82 | 0.75 mm² | Lamp cords, Speakers | 10A |
| 16 | 1.31 | 1.5 mm² | Extension leads | 13A |
| 14 | 2.08 | 2.5 mm² | USA 15A House Plugs | 15A |
| 12 | 3.31 | 4.0 mm² | USA 20A Kitchen Plugs | 20A |
| 10 | 5.26 | 6.0 mm² | Clothes Dryer, AC | 30A |
| 8 | 8.37 | 10.0 mm² | Large Appliances | 40A |
| 6 | 13.30 | 16.0 mm² | EV Chargers (Level 2) | 55A |
| 4 | 21.15 | 25.0 mm² | Sub-panels | 70A |
| 1/0 (0) | 53.49 | 50.0 mm² | Main Service Entry | 150A |
Calculation Formula
There is a mathematical relationship, though it's complex logarithmic math:
Diameter (mm) = 0.127 × 92^((36-AWG)/39)Pro Tip: Don't calculate this. Use the table above or our calculator.
Important: Solid vs Stranded
- Solid Core: One single piece of copper. The diameter matches the chart exactly.
- Stranded: Many small wires twisted together.
- A stranded 18 AWG wire has the same conductive amount of copper as a solid 18 AWG.
- BUT, the physical diameter is larger because of the air gaps between strands.
- Warning: When stripping stranded wire, be careful not to cut strands, or you reduce the gauge (e.g., turning 18 AWG into 20 AWG effectively).
Choosing the Right Wire
- Safety First: Never substitute a smaller wire (higher AWG) than specified.
- Metric Substitution: If a diagram asks for 14 AWG (2.08 mm²) and you are in Europe, use 2.5 mm². It is slightly larger and safer. Don't use 1.5 mm².
- Voltage Drop: For long runs (over 50ft/15m), always go up one size (e.g., use 10 AWG instead of 12 AWG) to ensure power gets to the end.
Conclusion
- US Wiring? Think 14, 12, 10 AWG.
- Metric Wiring? Think 1.5, 2.5, 4.0 mm².
- Always round UP to the nearest available standard size for safety.
Last Updated: February 9, 2026
Reading Time: 6 minutes