Foundations
Circular conductor area
- where
- conductor area (mm²)
- bare conductor diameter (mm)
Explain this equation
Works out the cross-sectional area of a round conductor from its diameter. Useful for checking a solid conductor or a single strand against its nominal size.
A is the copper or aluminium area in mm². d is the bare conductor diameter in mm, measured without insulation. π comes from the circle.
The area of a circle is πr², and the radius is half the diameter, so πr² becomes π(d/2)² = πd²/4. Area grows with the square of the diameter.
Sense check: a 2 mm diameter wire is about 3.14 mm². A 1.78 mm solid conductor is roughly 2.5 mm². Double the diameter and the area goes up four times.
Watch out: for stranded cable, the overall bundle diameter includes gaps. Work out one strand and multiply by the number of strands.
A circular conductor’s area depends on the square of its diameter. Divide diameter by two to get radius, or use πd²/4 directly.
For stranded conductors sum strand areas; the overall bundle diameter includes spaces and is not enough.
Enter your values to see the result.
Common mistake
Using insulation diameter as copper diameter.
Limits
Solid circular conductor, or diameter of one individual strand.
Sources
The tools calculate the displayed equation. They do not automatically choose cable sizes, approve installations, supply current regulatory tables, certify equipment or replace inspection and testing.