ASCII 35
Number Sign (#)
Printable ASCII
Number sign / hash / pound sign. Used for CSS IDs (#id), HTML fragments (#section), URL fragments, hashtags, and Markdown headings.
Common uses & context
The character '#' — Number Sign — has ASCII code 35 (0x23), octal 0043, binary 00100011. Number sign / hash / pound sign. Used for CSS IDs (#id), HTML fragments (#section), URL fragments, hashtags, and Markdown headings.
Punctuation and symbol codes carry the most syntactic weight per byte in programming: a single '#' can change how a parser reads an entire expression. When '#' needs to appear as literal data rather than syntax, you often have to escape it — in string literals, in regular expressions, in URLs (where it becomes %23), or in HTML. Knowing its exact code point (35) helps when you filter, validate, or sanitize input byte by byte.
All encodings at a glance
| Decimal | 35 |
| Hexadecimal | 0x23 |
| Octal | 0043 |
| Binary | 00100011 |
| HTML numeric entity | # |
| URL encoding | %23 |
| UTF-8 bytes | 0x23 |
Code snippets
JavaScript
String.fromCharCode(35); // "#"
35.toString(16); // "23"Python
chr(35) # '#'
ord(chr(35)) # 35
hex(35) # '0x23'HTML
# <!-- numeric entity (no named entity for this character) -->Programming notes
- ▸Code 35 (0x23); URL-encoded form%23.
- ▸In HTML the numeric entity is #.
- ▸When used as literal data in regex or strings, '#' usually needs escaping — check the rules for your language.
Frequently asked questions
What character is ASCII code 35?
ASCII code 35 is the character '#' (Number Sign). In hexadecimal it is 0x23, in octal 0043, and in binary 00100011.
What is 0x23 in ASCII?
Hexadecimal 0x23 equals decimal 35, which is the character '#' (Number Sign). To convert hex to ASCII yourself, read the two hex digits as a base-16 number (0x23 = 35) and look up that code point.
How do I write the character with code 35 in code?
In JavaScript use String.fromCharCode(35); in Python use chr(35); in HTML use the numeric entity #. In a URL it is percent-encoded as %23, and in UTF-8 it is stored as the byte sequence 0x23.