The petabit is a multiple of the unit bit for digital information or computer storage. The prefix peta (symbol P) is defined in the International System of Units (SI) as a multiplier of 1015 (1 quadrillion, short scale), and therefore
1 petabit = 1015bits = 1000000000000000bits = 1000 terabits.
The petabit has the unit symbol Pbit or Pb.
The petabit is closely related to the pebibit, a unit multiple derived from the binary prefix pebi of the same order of magnitude, which is equal to 250bits = 1125899906842624bits, or approximately 13% larger than the petabit.