AWG Wire Gauge Converter
Convert AWG wire gauge numbers to diameter in mm and cross-sectional area in mm².
How to use this tool
- Enter awg gauge in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your diameter and the full breakdown beneath it.
Convert any AWG wire gauge to diameter in millimetres and cross-sectional area in mm².
Formula
AWG diameter uses a logarithmic scale:
Diameter (mm) = 0.127 × 92(36 − AWG) / 39
Cross-sectional area (mm²) = π / 4 × diameter²
e.g. AWG 14: 0.127 × 92(36−14)/39 = 0.127 × 9222/39 ≈ 1.628 mm; area ≈ 2.081 mm²
How it works
The American Wire Gauge (AWG) system uses a geometric (logarithmic) progression: every 6 AWG steps roughly halve the cross-sectional area, and every 3 steps roughly halve the diameter. The anchor point is AWG 36 = 0.127 mm diameter, and the base of the exponent (92) reflects the ratio between AWG 0000 and AWG 36 diameters. Cross-sectional area is derived from the diameter via the standard circle area formula. A common mistake is assuming that a larger AWG number means a thicker wire — it is the opposite: AWG 14 is thicker than AWG 18, which is why heavier-duty circuits use lower AWG numbers (e.g. AWG 12 or 10 for 20–30 A circuits).
Worked example
Converting AWG 14 to diameter and cross-sectional area
- AWG = 14.
- Exponent: (36 − 14) / 39 = 22 / 39 ≈ 0.5641.
- Diameter: 0.127 × 92^0.5641 ≈ 0.127 × 12.819 ≈ 1.628 mm.
- Area: π / 4 × 1.628² ≈ 0.7854 × 2.650 ≈ 2.081 mm².
Diameter: 1.628 mm | Cross-Section: 2.081 mm²
Common mistakes to avoid
- Treating lower AWG numbers as thinner -- AWG is a reverse scale; AWG 14 is thicker than AWG 22. Wiring a circuit with too high an AWG number (thinner wire) for the current causes overheating and fire risk.
- Using the calculated area in mm2 to select a wire rated in kcmil (thousand circular mils) without converting -- 1 kcmil = 0.5067 mm2; these are different area units common in US versus EU electrical specs.
- Assuming the same AWG rating applies to both solid and stranded wire -- stranded wire of the same AWG has the same current capacity but a slightly larger overall diameter due to air gaps between strands.
Key terms
- AWG (American Wire Gauge)
- A standardised US wire sizing system where a higher gauge number denotes a thinner wire; commonly used for electrical wiring, hookup wire, and cable specifications.
- Cross-sectional area
- The area of the circular face of a wire, measured in mm²; it directly determines the wire's current-carrying capacity (ampacity) and its resistance per unit length.
- Ampacity
- The maximum continuous current a wire can safely carry without overheating, which depends primarily on cross-sectional area, insulation rating, and installation conditions.
- Logarithmic gauge scale
- AWG uses a geometric sequence so that equal steps in gauge number correspond to equal ratios in diameter; this means the relationship between AWG and diameter is exponential, not linear.
Frequently asked questions
- What is AWG 14 wire diameter?
- AWG 14 wire has a diameter of approximately 1.628 mm and a cross-sectional area of 2.08 mm². It is commonly used for 15-amp household circuits.