Convert circular inch to acre (US survey) [ac] Online | Free area Converter

Circular Inch


A circular inch is a unit of area used primarily in engineering and wire gauge measurements. It represents the area of a circle with a diameter of one inch.



  • Formula: Area = π × (radius)²



  • Since the radius is half an inch,

    Area = π × (0.5 in)² = π × 0.25 in² ≈ 0.7854 square inches (in²).



Circular inches are often used to specify cross-sectional areas of wires or pipes.


Acre (US Survey) [ac]


The acre (US survey) is a unit of area used mainly in the United States for land measurement, based on the US survey foot. It is slightly different from the international acre due to the foot definition.



  • 1 US survey acre = 43,560 US survey square feet



  • 1 US survey acre ≈ 4,046.87261 square meters



  • Slightly larger than the international acre by about 0.0005%.



It is commonly used in land surveying, real estate, and agriculture.




Popular Area Unit Conversions

Convert circular inch to Other Area Units