Attopascal Unit | All you need to know

The attopascal (symbol: aPa) is an SI-derived unit of pressure equal to one quintillionth (10^-18) of a pascal. It is an extremely small pressure unit used mainly in theoretical physics, nanotechnology, and scientific research involving ultra-low pressure measurements. The attopascal uses the SI prefix atto, representing a factor of 10^-18.

One attopascal is equal to 0.000000000000000001 pascal, 0.001 femtopascal, 0.000000001 nanopascal, 1×10^-23 bar, and 9.86923×10^-24 standard atmosphere. Although rarely used outside research, the attopascal is part of the complete SI pressure scale.