Byte-Size Measurement

Measuring Disk Storage Capacity

UnitEquivalent number of bytesWhat you might measure
1 byte8 bits*a character
1 kilobyte1,000 bytesemail message
1 megabyte1,000,000 bytestextbook
1 gigabyte1,000,000,000 bytesbookstore
1 terabyte1,000,000,000,000 bytesuniversity library
1 petabyte1,000,000,000,000,000 bytesfuture WWW
1 exabyte1,000,000,000,000,000,000 bytes?
1 zettabyte1,000,000,000,000,000,000,000 bytes?
1 yottabyte1,000,000,000,000,000,000,000,000 bytes?
*bit (BInary digiT) The smallest element of computer storage. It is a single digit in a binary number (0 or 1).

The bit is physically a transistor or capacitor in a memory cell, a magnetic domain on disk or tape, a reflective spot on optical media or a high or low voltage pulsing through a circuit. Groups of bits make up storage units in the computer, called characters, bytes, or words, which are manipulated as a group.

The most common is the byte, made up of eight bits and equivalent to one alphanumeric character. [Source: TechEncyclopedia]