ASCII 191
Inverted Question Mark (¿)
Latin-1 Supplement
Latin-1 character.
Common uses & context
Decimal 191 (0xBF) is Inverted Question Mark, part of the Latin-1 Supplement (128–255). Latin-1 character. It renders as '¿' and its binary byte is 10111111.
This is where single-byte ASCII ends and encoding matters. In Latin-1 (ISO-8859-1) '¿' is the single byte 0xBF. In UTF-8 — today's default for the web — the same character is the multi-byte sequence 0xC2 0xBF. Treating a Latin-1 byte as UTF-8 (or vice versa) is the usual reason accented letters and symbols turn into mojibake like é or €. The Unicode code point is U+00BF, and in HTML you can write it as ¿ or ¿.
All encodings at a glance
| Decimal | 191 |
| Hexadecimal | 0xBF |
| Octal | 0277 |
| Binary | 10111111 |
| HTML numeric entity | ¿ |
| HTML named entity | ¿ |
| URL encoding | %BF |
| UTF-8 bytes | 0xC2 0xBF |
Code snippets
JavaScript
String.fromCharCode(191); // "¿"
191.toString(16); // "bf"Python
chr(191) # control char ¿
ord(chr(191)) # 191
hex(191) # '0xbf'HTML
¿ <!-- named entity -->
¿ <!-- numeric entity -->Programming notes
- ▸Single byte 0xBF in Latin-1, but the multi-byte sequence 0xC2 0xBF in UTF-8 — never assume one byte per character above code 127.
- ▸Unicode code point U+00BF; HTML entity ¿.
- ▸If '¿' shows as mojibake, the encoding declared and the encoding used disagree — align both on UTF-8.
Unicode & UTF-8 note
In Unicode this is U+00BF. In UTF-8 it encodes to the byte sequence 0xC2 0xBF. In legacy Latin-1 (ISO-8859-1) it is a single byte 0xBF, which is why Latin-1 files often appear as mojibake when interpreted as UTF-8.
Frequently asked questions
What character is ASCII code 191?
ASCII code 191 is the character '¿' (Inverted Question Mark). In hexadecimal it is 0xBF, in octal 0277, and in binary 10111111.
What is 0xBF in ASCII?
Hexadecimal 0xBF equals decimal 191, which is the character '¿' (Inverted Question Mark). To convert hex to ASCII yourself, read the two hex digits as a base-16 number (0xBF = 191) and look up that code point.
How do I write the character with code 191 in code?
In JavaScript use String.fromCharCode(191); in Python use chr(191); in HTML use the numeric entity ¿ or the named entity ¿. In a URL it is percent-encoded as %BF, and in UTF-8 it is stored as the byte sequence 0xC2 0xBF.
Is '¿' part of standard ASCII?
No. Standard ASCII covers codes 0–127 only. '¿' is code 191, part of the Latin-1 Supplement (128–255, sometimes called "extended ASCII"). It is a single byte 0xBF in Latin-1 but a multi-byte sequence (0xC2 0xBF) in UTF-8.