Units of Information

A computer stores all information, whether text, pictures, sound or video, using only two symbols: 0 and 1. The smallest unit of information is the bit, which takes the value 0 or 1. Eight bits make 1 byte; one byte can store, for example, a single letter.

Larger units are used for large amounts: 1 kilobyte (KB) = 1024 bytes, 1 megabyte (MB) = 1024 KB, 1 gigabyte (GB) = 1024 MB, 1 terabyte (TB) = 1024 GB. When moving to a larger unit we divide by 1024, and when moving to a smaller unit we multiply by 1024. For example, 2 KB = 2 · 1024 = 2048 bytes.

The size of a text is easy to calculate: if each character takes 1 byte, a text of 500 characters takes 500 bytes. File size tells how much space the file occupies in the computer’s memory. For example, a 4 GB flash drive can hold four movies of 1 GB each.

Key takeaways

• A computer stores information as zeros and ones.
• The smallest unit is the bit; 8 bits = 1 byte.
• 1 KB = 1024 bytes, 1 MB = 1024 KB, 1 GB = 1024 MB.
• We divide by 1024 to move to a larger unit and multiply to move to a smaller one.