UTF-8

UTF-8 is a character encoding standard used for electronic communication. Defined by the Unicode Standard, the name is derived from Unicode Transformation Format – 8-bit. As of 2026, almost every webpage (99.1%) is transmitted as UTF-8. UTF-8 supports all 1,112,064 valid Unicode code points using a variable-width encoding of one to four one-byte (8-bit) code units. Code points with lower numerical values, which tend to occur more frequently, are encoded using fewer bytes. It was designed for backward compatibility with ASCII: 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, so that a UTF-8-encoded file using only those characters is identical to an ASCII file. Most software designed for any extended ASCII can read and write UTF-8, and this results in fewer internationalization issues than any alternative text encoding. UTF-8 is dominant for all countries/languages on the internet, is used in most standards, often the only allowed encoding, and is supported by all modern operating systems and programming languages.