UTF-8 stands for Unicode Transformation Format - 8-bit. It is a variable-width character encoding used for electronic communication. UTF-8 is capable of encoding all 1,112,064 valid Unicode code points using one to four one-byte (8-bit) code units¹.

How UTF-8 Works

UTF-8 encodes characters into one to four bytes, depending on the character's code point. The first 128 characters of Unicode, which correspond one-to-one with ASCII, are encoded using a single byte with the same binary value as ASCII. This means that any valid ASCII text is also valid UTF-8-encoded text¹.

For example, the Unicode code point for the euro sign (€) is U+20AC. In UTF-8, this character is encoded using three bytes: E2 82 AC. The encoding process involves distributing bits from the code point among the UTF-8 bytes and adding additional bits as required by the UTF-8 standard¹.

UTF-8's Advantages

• Backward Compatibility: UTF-8 is backward compatible with ASCII, which means ASCII text is also valid UTF-8 text. This compatibility helps in reducing internationalization issues and has led to widespread adoption in modern operating systems and standards like JSON¹.

• Efficiency: UTF-8 is efficient in encoding characters. Common characters use fewer bytes, which saves memory and reduces file size. Less common characters are encoded into two or more bytes, which is acceptable since they are used less frequently².

• Dominance on the Web: UTF-8 is the dominant encoding for the World Wide Web, accounting for a significant percentage of all web pages. It is also the only encoding allowed for Unicode in many web standards¹.