ISO88591UTF8

ISO88591UTF8 is not an official encoding name. It is sometimes used informally to describe a situation in which data labeled or assumed to be encoded in ISO 8859-1 (Latin-1) is interpreted as UTF-8, or vice versa. The term reflects a confusion or mismatch between two distinct character encodings used in computing.

ISO-8859-1 is an 8-bit single-byte encoding that encodes Western European characters. It maps each byte value 0x00 through 0xFF to a specific character, but it does not cover all Unicode characters. UTF-8 is a variable-length encoding capable of representing all characters defined by Unicode. Every code point in ISO-8859-1 has a corresponding Unicode point and can be encoded in UTF-8; conversely, a valid ISO-8859-1 byte sequence can be meaningfully converted to UTF-8.

In practice, encoding confusion can lead to mojibake when software misinterprets the byte stream. For example, text encoded in ISO-8859-1 might be decoded as UTF-8, resulting in garbled characters or replacement symbols. Conversely, text advertised as UTF-8 but stored as ISO-8859-1 can also produce incorrect output.

Best practice is to use UTF-8 for new data and to convert legacy ISO-8859-1 text to UTF-8 when possible. Clearly declare encoding in metadata, HTTP headers, or file formats, and employ robust charset detection and testing across platforms to minimize misinterpretation.

See also: UTF-8, ISO/IEC 8859-1, character encoding, mojibake, encoding conversion.