|Unit of Digital Information Storage|
|Petabyte|| 1015 Bytes|
|(larger units were proposed but have not yet formally been adopted by the BIPM)|
A petabyte (PB), derived from peta- prefix, is an International System of Units (SI) unit of digital information storage equal to 1000 terabyte. This unit is part of IEC 80000-13 (International System of Quantities) which requires this unit to always equal 1000 terabytes. A closely related unit, pebibyte, is used to represent 1024 tebibyte.