Convert AWG to diameter, area and resistance.
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How do you convert AWG to wire diameter, area and resistance?
Diameter d = 0.127 × 92^((36 − n) ÷ 39) mm, area = π⁄4 × d², and resistance = resistivity × length ÷ area. A higher AWG number means thinner wire, with more resistance. For example, AWG 12 is about 2.05 mm in diameter and 3.31 mm² in area; 100 m of copper has roughly 0.52 Ω.
Understanding your result
In AWG, a higher number means a thinner wire, and every six-gauge step roughly doubles or halves the cross-sectional area. Thinner wire has more resistance, which causes more voltage drop and heat for the same current.
Formula and method
Diameter d = 0.127 × 92^((36 − n) ⁄ 39) mm. Area = π⁄4 × d². Resistance = resistivity × length ⁄ area.
Worked example
AWG 12 is about 2.05 mm in diameter and 3.31 mm² in area; 100 m of copper has roughly 0.52 Ω.
How to use this tool
- Enter the AWG number.
- Optionally enter a length and material.
- Read the diameter, area and resistance.
Common mistakes to avoid
- Forgetting that a higher AWG number is a thinner wire.
- Using copper resistance figures for aluminium wire.
About the Wire Gauge (AWG) Calculator
The Wire Gauge Calculator converts an American Wire Gauge (AWG) number into the wire’s diameter, cross-sectional area and, for a given length, its resistance in copper or aluminium.
Who should use this tool
Electricians, electronics hobbyists and engineers selecting wire.
Benefits
- Diameter in mm and inches.
- Area in mm² and kcmil.
- Resistance for copper or aluminium.
- Shows the AWG formula.
Practical use cases
- Choosing wire for a circuit.
- Estimating voltage drop over a run.
- Converting AWG to metric sizes.
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Frequently asked questions
Does a higher AWG mean thicker or thinner?
Thinner. The gauge number rises as the wire gets smaller — AWG 12 is thicker than AWG 20.
How is resistance calculated?
Resistance = material resistivity × length ÷ cross-sectional area, assuming a solid round conductor at 20°C.