Byte

Standard Binary Storage Measurements

Byte

A byte is a unit of information that is eight bits (a binary 1 or 0) long. A byte is the unit most computers use to represent a character such as a letter, number or symbol (for example, "g", "5", "%"). A byte can also hold a string of bits that need to be used in some larger unit for application purposes (for example, the stream of bits that constitute a visual image for a program that displays images). A byte is abbreviated with a "B". (A bit is abbreviated with a small "b".) Computer storage is usually measured in byte multiples. Byte multiples are based on powers of 2 and commonly expressed as a "rounded off" decimal number.

Megabyte

A megabyte (abbreviated MB) is 2 to the 20th power bytes, or 1,048,576 bytes in decimal notation. According to the IBM Dictionary of Computing, when used to describe disk storage capacity and transmission rates, a megabyte is 1,000,000 (Million) bytes in decimal notation. According to the Microsoft Press Computer Dictionary, a megabyte means either 1,000,000 bytes or 1,048,576 bytes.

Gigabyte

A gigabyte (pronounced GIG-a-bite with hard G's) is 2 to the 30th power, or 1,073,741,824 (roughly a Billion) in decimal notation a thousand megabytes.

Terabyte

2 to the 40th power bytes or 1,099,511,627,776 bytes in decimal notation, which is approximately a thousand billion bytes (Trillion) or a thousand gigabytes.

Petabyte

2 to the 50th power bytes or 1,125,899,906,842,624 bytes in decimal notation (roughly a Quadrillion), which is approximately a thousand terabytes. A petabyte of storage is roughly the equivalent of 20 million four-drawer filing cabinets full of text.

Exabyte

2 to the 60th power bytes or 1,152,921,504,606,846,976 bytes in decimal. The prefix exa means one billion billion, or one Quintillion (10 to the 80^th power), which is a decimal term. It is common to say that an exabyte is approximately one quintillion bytes. In decimal terms, an exabyte is 1000 petabytes.

Zettabyte

2 to the 70th power bytes or 1,180,591,620,717,411,303,424 bytes in decimal (roughly a Sextillion). A zettabyte is equal to 1,024 exabytes. The name zetta was chosen because it's the last letter of the Latin alphabet and also sounds like the Greek letter Zeta.

Yottabyte

2 to the 80th power bytes or 1,208,925,819,614,629,174,706,176 bytes in decimal (roughly a Septillion). A yottabyte is equal to 1,024 zettabytes. The name yotta was chosen because it's the second-to-last last letter of the Latin alphabet and also sounds like the Greek letter iota.

To give an idea of the amount of data that is, imagine a stack of standard 1.5" 10Gb hard drives 2,665,482,734 miles high ! Or put another way, a line of CD-ROM’s from here to the Sun … and back … 1874 times !!!!! (348,104,319,023 miles)

Last Updated - 10/04/2000