ASCII 100
Latin Small Letter D (d)
Printable ASCII
Lowercase letter d. ASCII code 100. %d is the classic integer format specifier — the 'd' stands for decimal, unrelated to this glyph's value.
Common uses & context
Thelowercase letter 'd' has ASCII code 100 (0x64). Its uppercase twin 'D' sits exactly 32 code points away at 68. 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 d. ASCII code 100. %d is the classic integer format specifier — the 'd' stands for decimal, unrelated to this glyph's value.
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 'd' to its uppercase form youclear bit 5: 'd' & ~0x20 gives 'D'. 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.
'd' is also a hexadecimal digit: in base-16 it represents the value 13. Hex uses 0–9 for 0–15's firstten values and A–F (or a–f) for 10–15, so 'd' is valid inside literals like 0xdd and colour codes like #dddddd.
All encodings at a glance
| Decimal | 100 |
| Hexadecimal | 0x64 |
| Octal | 0144 |
| Binary | 01100100 |
| HTML numeric entity | d |
| URL encoding | %64 |
| UTF-8 bytes | 0x64 |
Code snippets
JavaScript
String.fromCharCode(100); // "d"
100.toString(16); // "64"Python
chr(100) # 'd'
ord(chr(100)) # 100
hex(100) # '0x64'HTML
d <!-- numeric entity (no named entity for this character) -->Programming notes
- ▸Case toggle: 'd' & ~0x20 = 'D' (a single-bit change).
- ▸Letter test: c >= 'a' && c <= 'z' — the lowercase block is contiguous (97–122).
- ▸As a hex digit, 'd' has value 13 in base-16.
Frequently asked questions
What character is ASCII code 100?
ASCII code 100 is the character 'd' (Latin Small Letter D). In hexadecimal it is 0x64, in octal 0144, and in binary 01100100.
What is 0x64 in ASCII?
Hexadecimal 0x64 equals decimal 100, which is the character 'd' (Latin Small Letter D). To convert hex to ASCII yourself, read the two hex digits as a base-16 number (0x64 = 100) and look up that code point.
How do I write the character with code 100 in code?
In JavaScript use String.fromCharCode(100); in Python use chr(100); in HTML use the numeric entity d. In a URL it is percent-encoded as %64, and in UTF-8 it is stored as the byte sequence 0x64.
What is the uppercase form of 'd' in ASCII?
'd' is code 100; its uppercase counterpart 'D' is code 68. The two always differ by 32, so you can convert by subtracting 32 (or clearing bit 0x20).