Convert Are (a) to Barn (b (area)) instantly.
About these units
Are (a)
An are is a metric land unit equal to 100 m², originally invented during the development of the metric system but now largely overshadowed by the hectare (100 ares). Although rarely used independently in modern measurement, the are survives in real estate transactions in parts of Europe, where small land parcels—such as garden plots or rural homesteads—may be expressed in ares. It remains important historically, as it served as a transitional unit bridging the earliest metric innovations with modern large-scale land measurement practices.
Barn (b (area))
The barn is an area unit used almost exclusively in nuclear and particle physics, equal to 10⁻²⁸ square meters. Despite its incredibly tiny size, the barn emerged from humorous origins: early nuclear physicists joked that certain atomic nuclei were "as big as a barn" compared to the particles trying to hit them. The barn quantifies interaction cross-sections—essentially probabilities of particles colliding or interacting with nuclei. Because fundamental forces operate at extremely small scales, typical cross-section values lie in the microbarn, nanobarn, or picobarn range. The barn is essential for describing reaction rates in particle accelerators, nuclear reactors, and astrophysical processes such as stellar fusion.