What is a character?

A character is a symbol that humans understand - like letters (a, ñ), numbers (3), or punctuation (?).

Computers, however, only understand binary numbers (0 or 1).

So, to represent characters in a computer, we need a mapping between characters and numbers.

What is a charset (character set)?

A charset (short for "character set") is basically a table that assigns a unique number (a code point) to each character.

For example, in the ASCII charset:

So when you type the letter "a", the computer actually stores the number 97 in memory.

An encoding defines how the numbers (code points) from a charset are stored in bytes.

Think of it like this:

Let’s look at "a" in several encodings:

Encoding	How "a" is stored (in bytes)	Explanation
ASCII	`01100001` → `0x61`	Only one byte (97 in decimal). ASCII supports 128 characters.
UTF-8	`01100001` → `0x61`	Same as ASCII for English letters. UTF-8 is backward compatible with ASCII.
UTF-16	`00000000 01100001` → `0x00 0x61`	Uses two bytes for basic Latin letters.
UTF-32	`00000000 00000000 00000000 01100001` → `0x00 0x00 0x00 0x61`	Always uses 4 bytes per character.

So for the same “a”:

ASCII only covers 128 characters - perfect for English, but not for other languages.

Unicode was created to represent all the world’s characters (like ñ, 你, or 😊).

Unicode assigns a unique number (code point) to every symbol.

For example:

UTF-8, UTF-16, and UTF-32 are different ways of encoding these Unicode code points.