Convert barn [b] to acre (US survey) [ac] Online | Free area Converter

Barn [b]


A barn (b) is a very small unit of area used mainly in nuclear and particle physics to measure the cross-sectional area of atomic nuclei and particles.

1 barn = 10⁻²⁸ square meters (m²).

The name "barn" humorously refers to something “as big as a barn” in the tiny world of atomic scales, despite its extremely small size.


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.




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