|Name||Symbol||Quantity||Expressed in terms of SI base units||Expressed in terms of other SI units|
|barn||b||area||10−28 m2||100 fm2
The barn, symbol b, is a non-SI unit of area. One barn is equal to 10−28 m2, or 100 fm2.
The barn is a non-SI unit of cross-section used in nuclear and particle interactions.