ISO-8859-1
How ISO-8859-1 works
ISO-8859-1 (Latin-1) extends ASCII to 256 characters by adding Western European accented letters, the pound sign, yen sign, and other symbols at positions 128-255. Published by ISO in 1987, it was the default encoding for HTTP/1.1 and early HTML before UTF-8 took over.
Positions 128-159 are undefined in ISO-8859-1 (reserved for control codes), but Windows-1252 fills those 32 slots with characters like curly quotes, the euro sign, and the trademark symbol. This difference is the most common source of confusion: a file labeled "iso-8859-1" often actually uses Windows-1252. Web browsers silently treat ISO-8859-1 as Windows-1252 for this reason. Compare the two encodings to see exactly which positions differ.
Positions 128-159 are undefined in ISO-8859-1 (reserved for control codes), but Windows-1252 fills those 32 slots with characters like curly quotes, the euro sign, and the trademark symbol. This difference is the most common source of confusion: a file labeled "iso-8859-1" often actually uses Windows-1252. Web browsers silently treat ISO-8859-1 as Windows-1252 for this reason. Compare the two encodings to see exactly which positions differ.