U+2205 · Math symbol
HTML entity
∅
LaTeX
\varnothing
Empty Set Symbol ∅
∅ is empty set, U+2205. Unicode also records it as “null set”. It was added in Unicode 1.1, and Unicode files it under Math symbol.
Also known as
- null set
What Unicode says about ∅
used in linguistics to indicate a null morpheme or phonological "zero"
— annotation from the Unicode Standard, NamesList.txt
Codes & technical data
| Unicode | U+2205 | |
|---|---|---|
| HTML hex | ∅ | |
| HTML decimal | ∅ | |
| CSS | \2205 | |
| JavaScript | \u{2205} | |
| Python | \U00002205 | |
| Java / C# | \u2205 | |
| Rust | \u{2205} | |
| Swift | \u{2205} | |
| PHP | \u{2205} | |
| URL encoded | %E2%88%85 | |
| UTF-8 bytes | E2 88 85 | |
| UTF-16 bytes | 2205 | |
| Base64 | 4oiF | |
| Decimal | 8709 | |
| HTML entity | ∅ | |
| LaTeX | \varnothing | |
| Category | Math symbol (Sm) | |
| Introduced | Unicode 1.1 | |
Will ∅ survive being pasted?
- Normalisation. Yes. ∅ is unchanged by NFKC, so it survives normalising systems intact.
- Legacy encodings. ∅ is Unicode-only — it has no Latin-1 equivalent, so a system stuck on an 8-bit encoding cannot represent it.
- Size. 3 bytes in UTF-8. Character-limited fields — SMS, bios, some form validators — usually count bytes, not characters.
Unicode cross-references
The standard points readers of ∅ at these characters — usually because they look alike, or because one is the correct choice where the other is often used by mistake.
Nearby in Mathematical Operators
The operators mathematics and programming share — set theory, logic, calculus, comparison. Almost every character here has a LaTeX command, which is usually the fastest way to name the one you mean.
How to type ∅
| Windows | Type 2205 then press Alt+X |
|---|---|
| macOS | Press Ctrl+Cmd+Space, then search for “empty set” |
| Linux | Press Ctrl+Shift+U, type 2205, press Enter |
| HTML | ∅ |
About Unicode’s Math symbol category
Unicode classifies this as a mathematical symbol, which means software that lays out formulas treats it as an operator or relation and gives it spacing accordingly, rather than setting it tight against its neighbours like a letter.
Frequently asked questions
- How do I type the ∅ empty set symbol?
- On Windows, type 2205 and press Alt+X. On Linux press Ctrl+Shift+U then 2205. On any system the quickest route is the copy button on this page.
- What is the code for ∅?
- Empty Set is U+2205, written in HTML as ∅ and in LaTeX as \varnothing. In UTF-8 it takes 3 bytes. The table above lists every escape format.
- What kind of character is ∅?
- Empty Set is filed under Math symbol in the Mathematical Operators block, and was introduced in Unicode 1.1. Unicode classifies this as a mathematical symbol, which means software that lays out formulas treats it as an operator or relation and gives it spacing accordingly, rather than setting it tight against its neighbours like a letter.