The petabyte is a multiple of the unit byte for digital information. The prefix peta indicates the fifth power of 1000 and means 1015 in the International System of Units (SI), and therefore 1 petabyte is one quadrillion (short scale) bytes, or 1 billiard (long scale) bytes. The unit symbol for the petabyte is PB. 1 PB = = = . A related unit, the pebibyte (PiB), using a binary prefix, is the corresponding fifth power of 1024, which is more than 12% greater (250 bytes = ).