Double integral (∬) is the Unicode character at U+222C in the Mathematical Operators block. Official name: DOUBLE INTEGRAL. It is used in multivariable calculus for integrals over a 2D region (e.g. ∬Df(x,y) dA).
Remember
Character ∬
Unicode U+222C
Named entity ∬
Hex entity ∬
Decimal ∬
CSS escape \222C
Not the same ∫ · ∭ · ∮
Prefer ∬ in HTML markup (alias: &iint;; case-sensitive name). You can also type ∬ in UTF-8, or use numeric forms when needed.
Double integral rendered alone and in a short calculus expression.
Example∬D f(x,y) dA
Large glyph∬
Compared∬ ∫ ∭ ∮
With entitiesNamed: ∬ | Hex: ∬ | Decimal: ∬
Code
Complete HTML Example
One page that shows Double Integral with named, hex, decimal, CSS escape, and a typed character. Use View Output or open the live editor.
Named + Hex + Decimal + CSS + Typed
Five ways to produce ∬, plus a short calculus example.
html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Double Integral (∬) in HTML</title>
<style>
#point::after {
content: "\222C";
}
</style>
</head>
<body>
<p>Double Integral using Named Entity: ∬</p>
<p>Double Integral using Hex Code: ∬</p>
<p>Double Integral using HTML Code: ∬</p>
<p id="point">Double Integral using CSS Entity: </p>
<p>Typed directly: ∬</p>
<p>Calculus: ∬<sub>D</sub> f(x,y) dA</p>
</body>
</html>
Double Integral using Named Entity: ∬
Double Integral using Hex Code: ∬
Double Integral using HTML Code: ∬
Double Integral using CSS Entity: ∬
Typed directly: ∬
Calculus: ∬D f(x,y) dA
How It Works
1. Named:∬ is the HTML5 name for U+222C → ∬. Best default in markup (&iint; is the same glyph).
2. Hex:U+222C → ∬ in HTML. Same glyph as the named form.
3. Decimal: same code point as 8748 → ∬. Same result as hex and named.
4. CSS: use \222C in content (not an HTML entity). #point::after appends that ∬ after the paragraph text.
5. Typed / calculus: paste ∬ in UTF-8, or write ∬<sub>D</sub> f(x,y) dA.
Pitfalls & Tips
Common mistakes when working with Double Integral.
Case
Case-sensitive name
Write ∬ (capital I). ∫ is the single integral ∫.
∫
Not a single integral
Use ∫ for ∫. Use ∬ for ∬ over a region.
∭
Related: triple integral
∭ (∭) is for volume integrals — not the same as ∬.
CSS vs HTML
Do not mix escapes
\222C belongs in CSS strings. ∬ / ∬ / ∬ belong in HTML.
Fonts
Math font coverage
Some fonts omit U+222C. Prefer a font with Mathematical Operators coverage for display.
Semicolon
End references
Always finish with ; — write ∬, not &Int.
Compatibility
Browser Support
Double integral (U+222C) and its entity forms (∬, &iint;, ∬, ∬, CSS \\222C) are supported in all mainstream browsers. Visible glyphs depend on math font coverage.
✓ Universal support
Double Integral (∬)
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+222C / entitiesFull support
Bottom line: Prefer ∬ in HTML (alias &iint;). Use ∬ or ∬ when numeric form is required, and \\222C only inside CSS content.
Remember
Key Takeaways
Unicode: double integral is U+222C (decimal 8748) — glyph ∬.
HTML: prefer ∬ (or &iint;), or use ∬ / ∬ / type ∬.
CSS: use \222C inside content for generated text.
Meaning:∬ = double / area integral — not ∫, ∭, or ∮.
One line:U+222C → ∬ / ∬ / ∬ / CSS \222C / type ∬.
Frequently Asked Questions
Use ∬ or &iint; (named), ∬ (hex), ∬ (decimal), type ∬ directly in UTF-8, or the CSS escape \222C in content. Prefer ∬ in normal HTML.
U+222C (DOUBLE INTEGRAL). Hex 222C, decimal 8748. It belongs to the Mathematical Operators block (U+2200–U+22FF).
Yes. Use ∬ (preferred) or &iint;. Numeric forms ∬ and ∬ also work. Note that ∬ is case-sensitive.
Use it in multivariable calculus for integrals over a 2D region (area integrals). Prefer ∫ (∫) for single integrals and ∭ (∭) for triple integrals.
HTML entities (∬, ∬, or ∬) go in markup. The CSS escape \222C goes in stylesheet strings (usually content on ::before/::after).
No. ∬ / &iint; is U+222C (∬). ∫ is U+222B (∫). Case matters for ∬.
🤔
Did you know?
Double integral is Unicode U+222C (decimal 8748) — glyph ∬ in the Mathematical Operators block. HTML5 names it ∬ (also &iint;). Use it for area integrals over a region, e.g. ∬_D f(x,y) dA. The single integral is ∫ (∫).
