Number sign (#) is the Unicode character at U+0023 in the Basic Latin (ASCII) block. Official name: NUMBER SIGN. Also known as hash, pound, or octothorpe — used for hashtags, labels, and CSS id selectors.
Remember
Character #
Unicode U+0023
Named entity #
Hex entity #
Decimal #
CSS escape \23
Not the same № · ♯ · %
Prefer typing # or # in HTML markup. Numeric forms work the same when you need an explicit entity.
Symbol using Named Entity: #
Symbol using Hex Code: #
Symbol using HTML Code: #
Symbol using CSS Entity: #
Typed directly: #
Example: Tag #HTML
How It Works
1. Named:# is the HTML5 name for U+0023 → #. Useful when you want a readable entity.
2. Hex:U+0023 → # in HTML. Same glyph as the named form.
3. Decimal: same code point as 35 → #. Same result as hex and named.
4. CSS: use \23 in content (not an HTML entity). #point::after appends that # after the paragraph text. You can also write content: "#".
5. Typed / example: paste # in UTF-8, or write #HTML for a hashtag-style label.
Pitfalls & Tips
Common mistakes when working with Number Sign.
ASCII
Typing # is fine
Number sign is ASCII. You do not need an entity unless you prefer one for consistency or generated markup.
№
Not the numero sign
№ (№) means “number” / “No.” Use # for hash and labels, not as a substitute for №.
♯
Not music sharp
Formal music notation uses ♯ (♯). Do not replace it with # in scores or theory text.
CSS vs HTML
Do not mix escapes
\23 belongs in CSS strings. # / # / # belong in HTML.
Selectors
Id selectors vs the glyph
In CSS, #header starts an id selector. That is syntax, not the character entity. Document the glyph with entities or a typed # in prose.
Semicolon
End references
Always finish named/numeric forms with ; — write #, not &num.
Compatibility
Browser Support
Number sign (U+0023) and its entity forms (#, #, #, CSS \\23) are supported in all mainstream browsers. As ASCII, the glyph is available in essentially every font.
✓ Universal support
Number Sign (#)
Encode with named, hex, decimal, CSS escape, or type the character — same code point everywhere encoding is supported.
100%Browser coverage
Google ChromeSupported
Yes
Microsoft EdgeSupported
Yes
Mozilla FirefoxSupported
Yes
Apple SafariSupported
Yes
OperaSupported
Yes
Internet ExplorerAll versions
Yes
U+0023 / entitiesFull support
Bottom line: Prefer typing # or # in HTML. Use # or # when numeric form is required, and \\23 only inside CSS content.
Remember
Key Takeaways
Unicode: number sign is U+0023 (decimal 35) — glyph #.
HTML: type #, or use # / # / #.
CSS: use \23 or "#" inside content for generated text.
Meaning:# = hash / number sign — not № or ♯.
One line:U+0023 → type # / # / # / # / CSS \23.
Frequently Asked Questions
Type # directly, or use # (named), # (hex), # (decimal), or the CSS escape \23 in content. Prefer typing # or # in normal HTML.
U+0023 (NUMBER SIGN). Hex 23, decimal 35. It belongs to the Basic Latin (ASCII) block (U+0000–U+007F).
Yes. Use #. Numeric forms # and # also work. Typing # is fine in UTF-8 documents.
Use it for hashtags, item or issue numbers (Item #1), CSS id-selector docs, and any text that needs the hash or pound symbol.
HTML entities (#, #, or #) go in markup. The CSS escape \23 goes in stylesheet strings (usually content on ::before/::after).
No. # is U+0023 (number sign). № is U+2116 (numero sign). ♯ is U+266F (music sharp). Use the correct character for each meaning.
🤔
Did you know?
Number sign is Unicode U+0023 (decimal 35) — glyph # in the Basic Latin (ASCII) block. Also called hash, pound, or octothorpe. HTML5 names it #. Do not confuse it with № (№) or music sharp ♯ (♯).
