A byte is a measurement of data that contains eight bits, which is the smallest increment of data on a computer. It’s the smallest addressable unit of memory in most computer architectures, and network protocol documents such as the Internet Protocol refers to an 8-bit byte as an octet. A single byte can be used to represent 2 to the 8th or 256 different values.

The byte was originally created to store a single character, since 256 values is adequate enough to represent all lowercase and uppercase letters, numbers, and symbols in western languages. For example, bytes can represent the letter N, a comma, a percentage sign, or any number from 0 to 256. While the byte was designed to store character data, it has become the fundamental unit of measurement for data storage. But because a byte contains so little storage, the processing and storage capacities of computer hardware are typically in gigabytes (GB) and terabytes (TB).

Byte prefixes

The prefix preceding byte helps identify the size of a byte and how much data is contained within it. Commonly used prefixes include:

  • Kilobyte (KB): A small email without images is approximately 2 KB.
  • Megabyte (MB): A song is approximately 3-4 MB.
  • Gigabyte (GB): A standard DVD may hold up to 4.7 GB of data.
  • Terabyte (TB): 500 hours worth of movies or 310,000 pictures is a TB.
  • Petabyte (PB): 500 billion pages of standard typed text is approximately 1 PB.

For a visual representation of byte size and exact numbers, consider the chart below. It’s worth noting byte sizes are not evenly rounded off (1,024 instead of 1,000 bytes) because computers use binary math instead of a decimal system.


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