A byte is a unit of measurement used to measure data. One byte contains eight binary bits, or a series of eight zeros and ones. Therefore, each byte can be used to represent 2^8 or 256 different values.
The byte was originally developed to store a single character, since 256 values is sufficient to represent all standard lowercase and uppercase letters, numbers, and symbols. However, since some languages have more than 256 characters, modern character encoding standards, such as UTF-16, use two bytes, or 16 bits for each character.
While the byte was originally designed to measure character data, it is now the fundamental unit of measurement for all data storage. For example, a kilobyte contains 2^10 or 1,024 bytes. A megabyte contains 1,024 x 1,024, or 1,048,576 bytes. Since bytes are so small, they are most often used to measure specific data within a file, such as pixels or characters. Even the smallest files are typically measured in kilobytes, while data storage limits are often measured in gigabytes or terabytes.