A 1-KB file is composed of 1,000 bytes of data, a 1-MB file is composed of 1 million bytes of data and a 1-GB file is composed of 1 billion bytes of data. "KB" stands for "kilobytes," "MB" stands for "megabytes" and "GB" stands for "gigabytes," as "kilo," "mega" and "giga" are metric system prefixes for thousand, million and billion. The abbreviation for byte is "B."
A byte is composed of 8 bits of data. A bit is equivalent to a single 0 or 1 in the machine language of a computer. A byte is equivalent to a single keystroke on a typical personal computer. A line of text created with 70 keystrokes is 70 bytes or 560 bits. A half-page of text when saved creates a file about 1 kilobyte in size.
Some examples of information that saves as about a 1-megabyte file include a typical minute of CD-quality audio, a 500-page novel or a 4-megapixel photo. Examples of a 1-gigabyte file are a two-hour movie in high-quality MP3 format or a about a thousand 500-word novels saved as a single file.
Typical CDs store about 700 megabytes, while typical DVDs store about 6 gigabytes. A typical hard drive in a personal computer produced in 2015 stores about 1 terabyte of data. A terabyte is 1 trillion bytes, or about 1,000 gigabytes.