AWG to mm Calculator
Convert American Wire Gauge (AWG) to millimetres diameter and mm² cross-section. Full table for all standard AWG sizes with resistance and current ratings.
Or enter custom AWG number:
12 AWG Diameter
2.053 mm
0.08083" · 3.3103 mm²
Diameter (mm)
2.053 mm
Diameter (inches)
0.08083"
Area (mm²)
3.3103 mm²
Area (kcmil)
6532.97 kcmil
Resistance (Ω/m)
0.005296 Ω/m
Max Current
20 A
About the AWG to mm Calculator
An AWG to mm calculator converts American Wire Gauge numbers to metric diameter in millimetres and cross-sectional area in mm² — essential for international electrical projects, European component sourcing, engineering specifications, and understanding wire specifications across US and metric systems. AWG (American Wire Gauge) and the metric system (mm²) are the two dominant wire sizing standards in the global electrical industry. AWG is used in the USA, Canada, and many countries influenced by US standards; mm² is the metric system used throughout Europe, Australia, UK (for modern wiring), Asia, South America, and most of the world under IEC standards. The AWG system is counterintuitive: larger numbers mean thinner wire (AWG 22 is much thinner than AWG 10), and the scale is logarithmic with AWG based on the number of wire drawing operations needed to reach the final diameter. Our calculator provides exact diameter and area conversions for all standard AWG sizes from 4/0 (0000 = −3 in our notation, 11.68 mm) to 26 AWG (0.405 mm), along with resistance per metre and NEC ampacity for each size. A complete AWG comparison table is included for quick reference.
Formula
d (in) = 0.005 × 92^((36-AWG)/39) | d (mm) = d (in) × 25.4 | A (mm²) = π × (d/2)² | kcmil = (d_in × 1000)²
How It Works
The AWG diameter formula: d (inches) = 0.005 × 92^((36-AWG)/39). Converting to mm: d (mm) = d (inches) × 25.4. For negative AWG numbers: AWG 0 = 8.251 mm; AWG 00 (2/0) = 9.266 mm; AWG 000 (3/0) = 10.405 mm; AWG 0000 (4/0) = 11.684 mm. Cross-sectional area: A = π × (d/2)² mm². Resistance (copper at 20°C): R = ρ × L / A = 1.724×10⁻⁸ Ω·m × L / A m². Key equivalents: AWG 14 = 1.628 mm = 2.08 mm² (US standard for 15A circuits); AWG 12 = 2.053 mm = 3.31 mm² (20A circuits); AWG 10 = 2.588 mm = 5.26 mm² ≈ EU 6 mm² (30A circuits). EU wiring cross-section equivalents: 1.5 mm² ≈ AWG 15; 2.5 mm² ≈ AWG 13; 4 mm² ≈ AWG 11; 6 mm² ≈ AWG 10; 10 mm² ≈ AWG 8.
Tips & Best Practices
- ✓AWG to mm² equivalents for sourcing: when purchasing wire in Europe for US projects (or vice versa): 14 AWG → use 1.5 mm² (slightly undersized) or 2.5 mm² (oversized); 12 AWG → use 2.5 mm²; 10 AWG → use 4 mm² or 6 mm²; 8 AWG → use 6 mm² or 10 mm². Always verify ampacity under the applicable national standard.
- ✓kcmil (thousand circular mils): US large cable sizes are specified in kcmil rather than AWG. 1 kcmil = 0.5067 mm². Common sizes: 250 kcmil = 126.7 mm²; 350 kcmil = 177.4 mm²; 500 kcmil = 253.4 mm²; 750 kcmil = 380.1 mm². For service entrance cables, US specs use kcmil while EU specs use mm².
- ✓Solid vs stranded wire: same AWG rating but different physical construction. Solid wire (single conductor) is used for in-wall residential wiring (Romex). Stranded wire (multiple thin conductors twisted together) is more flexible and used for appliance cords, chassis wiring, and anything that needs to bend repeatedly. Both have the same electrical resistance at the same AWG.
Who Uses This Calculator
Electrical engineers working on international projects who need to specify or procure wire using one standard when the other is required. Electronics designers sourcing wire for PCB harnesses and panel wiring across different regions. Hobbyists and makers understanding wire sizing when components specify AWG but local suppliers stock metric mm². Inspectors and engineers verifying that imported equipment with AWG-specified wiring meets local mm²-based code equivalents.
Optimised for: USA · UK · Canada · Australia · Calculations run in your browser · No data stored
Frequently Asked Questions
What is AWG 14 in mm?
14 AWG = 1.628 mm diameter = 2.08 mm² cross-section. It is the minimum size for 15A general-purpose circuits in the US and Canada. In European systems, the closest metric equivalent is 1.5 mm² for 15A circuits.
What is AWG 12 in mm?
12 AWG = 2.053 mm diameter = 3.31 mm² cross-section, rated 20A. European equivalent: 2.5 mm². This is the standard wire for 20A kitchen and bathroom circuits, dishwashers, and GFCI-protected outlets.
Is AWG the same as mm²?
No — AWG is an American standard based on wire diameter using a logarithmic scale; mm² is the metric cross-sectional area system used in Europe, Australia, and internationally. An AWG 10 wire ≈ 5.26 mm²; EU 6 mm² wire ≈ AWG 10. They are related but not directly equivalent.
What AWG is 2.5 mm² wire?
2.5 mm² (EU standard for 20A circuits) ≈ AWG 13. The closest standard AWG sizes are 12 AWG (3.31 mm², slightly larger) and 14 AWG (2.08 mm², slightly smaller). For rewiring projects, use 12 AWG as the safe equivalent.