Character representation

A text character is a letter, digit, punctuation mark, or other symbol that you might type in on your keyboard.

Computers store characters as numbers – each letter or other symbol has a unique number (for example, A might be represented by the number 65, B by 66 etc). A character string such as "Hello world!" is represented by a list of numbers.

A character set is a list of all the characters which are recognised by a computer's hardware and software. It also defines which number is used to represent each character. Here is a simple character set which just contains the capital letters, and gives each letter a different number to identify it:

In order to transfer text data between different computer systems, we need to use a standard character set that all computers understand. There are two standard character sets which are very widely used - ASCII and Unicode.

See also

• Binary
• Bits and bytes
• Units of storage
• Powers of two
• Representing numbers
• Binary numbers
• Hexadecimal numbers
• Adding binary numbers
• Negative binary numbers
• Bitwise logical operations
• Binary shift
• ASCII
• Extended ASCII
• Unicode
• Digital images
• Bitmap images
• Computer colour
• Colour depth
• Vector images
• Image file formats
• Computer sound
• Recording sound
• Playing sound
• Sound file formats