ASCII 121
Latin Small Letter Y (y)
Printable ASCII
Lowercase letter y. ASCII code 121.
Common uses & context
Thelowercase letter 'y' has ASCII code 121 (0x79). Its uppercase twin 'Y' sits exactly 32 code points away at 89. That constant gap of 32 — a single bit, 0x20 — is why changing letter case is one of the cheapest operations a CPU can do: you flip or mask one bit rather than looking anything up. Lowercase letter y. ASCII code 121.
The lowercase Latin letters form the contiguous block 97–122, so range checks like c >= 'a' && c <= 'z' work without a lookup table. To convert 'y' to its uppercase form youclear bit 5: 'y' & ~0x20 gives 'Y'. Because uppercase (65–90) sorts before lowercase (97–122) in raw byte order, naive sorting places every capitalized wordahead of every lowercase one — the reason "Zebra" comes before "apple" unless you sort case-insensitively.
All encodings at a glance
| Decimal | 121 |
| Hexadecimal | 0x79 |
| Octal | 0171 |
| Binary | 01111001 |
| HTML numeric entity | y |
| URL encoding | %79 |
| UTF-8 bytes | 0x79 |
Code snippets
JavaScript
String.fromCharCode(121); // "y"
121.toString(16); // "79"Python
chr(121) # 'y'
ord(chr(121)) # 121
hex(121) # '0x79'HTML
y <!-- numeric entity (no named entity for this character) -->Programming notes
- ▸Case toggle: 'y' & ~0x20 = 'Y' (a single-bit change).
- ▸Letter test: c >= 'a' && c <= 'z' — the lowercase block is contiguous (97–122).
Frequently asked questions
What character is ASCII code 121?
ASCII code 121 is the character 'y' (Latin Small Letter Y). In hexadecimal it is 0x79, in octal 0171, and in binary 01111001.
What is 0x79 in ASCII?
Hexadecimal 0x79 equals decimal 121, which is the character 'y' (Latin Small Letter Y). To convert hex to ASCII yourself, read the two hex digits as a base-16 number (0x79 = 121) and look up that code point.
How do I write the character with code 121 in code?
In JavaScript use String.fromCharCode(121); in Python use chr(121); in HTML use the numeric entity y. In a URL it is percent-encoded as %79, and in UTF-8 it is stored as the byte sequence 0x79.
What is the uppercase form of 'y' in ASCII?
'y' is code 121; its uppercase counterpart 'Y' is code 89. The two always differ by 32, so you can convert by subtracting 32 (or clearing bit 0x20).