Why is the default 8-bit codepage called "ANSI"?

Raymond Chen


Reader Ben Hutchings wanted to know why the 8-bit codepage is called “ANSI” when it isn’t actually ANSI.

But instead of saying, “Oh well, some things mortals were never meant to know,” he went and dug up the answer himself.

A quick Google for Windows ANSI misnomer found me exactly what I was looking for [pdf]:

“The term “ANSI” as used to signify Windows code pages is a historical reference, but is nowadays a misnomer that continues to persist in the Windows community. The source of this comes from the fact that the Windows code page 1252 was originally based on an ANSI draft, which became ISO Standard 8859-1. However, in adding code points to the range reserved for control codes in the ISO standard, the Windows code page 1252 and subsequent Windows code pages originally based on the ISO 8859-x series deviated from ISO. To this day, it is not uncommon to have the development community, both within and outside of Microsoft, confuse the 8859-1 code page with Windows 1252, as well as see “ANSI” or “A” used to signify Windows code page support.

Raymond Chen
Raymond Chen

Follow Raymond