What Does Petabyte Mean?

A petabyte (PB) is a unit of digital information storage used to denote the size of data. It is equivalent to 1,024 terabytes or 1,000,000,000,000,000 bytes.


Techopedia Explains Petabyte

The prefix "peta" is part of the International System of Units (SI). It means 1015 units. Hard disk manufacturers label their products in SI units, which may confuse some people in the IT field. The ISO, IEEE and the IEC all recommend using the unit pebibyte, which signifies 250 bytes and is more accurate for the measure of bytes.

Two interpretations can be made using the two standards:

  • Using SI, one petabyte is equivalent to 1,000 terabytes, or 1015 bytes.
  • Using traditional binary measurement, one petabyte is equivalent to 1,125,899,906,842,624 bytes, that’s 250 bytes, also equivalent to 1 pebibyte (PiB).

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Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.