U+222C · Math symbol
HTML entity
∬
LaTeX
\iint
Double Integral Symbol ∬
∬ is double integral, U+222C. Unicode records it as a compatibility form of ∫∫ (compat form). It was added in Unicode 1.1, and Unicode files it under Math symbol.
Codes & technical data
| Unicode | U+222C | |
|---|---|---|
| HTML hex | ∬ | |
| HTML decimal | ∬ | |
| CSS | \222C | |
| JavaScript | \u{222C} | |
| Python | \U0000222C | |
| Java / C# | \u222C | |
| Rust | \u{222c} | |
| Swift | \u{222C} | |
| PHP | \u{222C} | |
| URL encoded | %E2%88%AC | |
| UTF-8 bytes | E2 88 AC | |
| UTF-16 bytes | 222C | |
| Base64 | 4ois | |
| Decimal | 8748 | |
| HTML entity | ∬ | |
| LaTeX | \iint | |
| Decomposes to | ∫∫ (compat form) | |
| Category | Math symbol (Sm) | |
| Introduced | Unicode 1.1 | |
Will ∬ survive being pasted?
- Normalisation. No. Anything that applies NFKC — search indexes, usernames, domain names, programming identifiers — rewrites ∬ as
∫∫. Safe for display, not for storage. - 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.
Other integral characters
Unicode names 11 characters ending in “integral”. They differ by direction, weight or decoration rather than by meaning.
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 222C then press Alt+X |
|---|---|
| macOS | Press Ctrl+Cmd+Space, then search for “double integral” |
| Linux | Press Ctrl+Shift+U, type 222c, 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 ∬ double integral symbol?
- On Windows, type 222C and press Alt+X. On Linux press Ctrl+Shift+U then 222c. On any system the quickest route is the copy button on this page.
- What is the code for ∬?
- Double Integral is U+222C, written in HTML as ∬ and in LaTeX as \iint. In UTF-8 it takes 3 bytes. The table above lists every escape format.
- Will ∬ survive being pasted anywhere?
- Not always. Double Integral is a compatibility character: any system that applies Unicode NFKC normalisation — search indexes, usernames, identifiers — replaces it with ∫∫. Use it for display, not where text is normalised.