HTML Entity for Double Integral (∬)
What You'll Learn
How to display the Double Integral (∬) in HTML using named, hexadecimal, decimal, and CSS entity methods. This character is U+222C (DOUBLE INTEGRAL) in the Mathematical Operators block (U+2200–U+22FF)—used in multivariable calculus for integrals over a region in the plane.
Render it with ∬, ∬, ∬, or CSS escape \222C. For a single integral use ∫ (∫); for triple integral use ∭ (∭).
⚡ Quick Reference — Double Integral
U+222CMathematical Operators block
∬Hexadecimal reference
∬Decimal reference
∬Most readable option
Name Value
──────────── ──────────
Unicode U+222C
Hex code ∬
HTML code ∬
Named entity ∬
CSS code \222CComplete HTML Example
This example demonstrates the Double Integral symbol (∬) using hexadecimal code, decimal HTML code, the named entity, and a CSS content escape on a pseudo-element:
<!DOCTYPE html>
<html>
<head>
<style>
#point:after{
content: "\222C";
}
</style>
</head>
<body>
<p>Double Integral using Hexadecimal: ∬</p>
<p>Double Integral using HTML Code: ∬</p>
<p>Double Integral using Named Entity: ∬</p>
<p id="point">Double Integral using CSS Entity: </p>
</body>
</html>🌐 Browser Support
U+222C is supported in modern browsers; use a font with Mathematical Operators coverage for consistent glyphs:
👀 Live Preview
See the Double Integral (∬) in calculus and scientific notation:
🧠 How It Works
Named Entity
∬ is the HTML named entity for the Double Integral (∬) — the most readable option in source code.
Hexadecimal Code
∬ uses the Unicode hexadecimal value 222C to display the Double Integral symbol. The x prefix indicates hexadecimal format.
Decimal HTML Code
∬ uses the decimal Unicode value 8748 to display the same character.
CSS Entity
\222C is used in CSS stylesheets, particularly in the content property of pseudo-elements like ::before and ::after.
Same visual result
All four methods produce: ∬. Unicode U+222C. Not single integral ∫ (∫) or triple integral (∭).
Use Cases
The Double Integral symbol (∬) commonly appears in the following scenarios:
Double integrals over regions (e.g. ∬D f(x,y) dA), area and volume calculations.
Flux, surface integrals, and formulas using double integration.
Online courses and tutorials with correct calculus notation in HTML.
Articles and docs that need ∬ alongside MathML or equation renderers.
Pair with MathML or descriptions so assistive tech interprets formulas.
Unicode and HTML entity guides for Mathematical Operators.
💡 Best Practices
Do
- Prefer
∬for readable HTML source - Use ∬ for double integrals over planar regions
- Use fonts that cover Mathematical Operators (U+2200–U+22FF)
- For complex equations, consider MathML, MathJax, or KaTeX
- Pick one entity style per project for consistency
Don’t
- Confuse ∬ (double) with ∫ (
∫, single) or ∭ (triple) - Use CSS escape
\222Cinside HTML markup - Rely on plain HTML entities alone for full limit/subscript notation
- Mix hex, decimal, and named styles randomly in one file
- Forget UTF-8 (
<meta charset="utf-8">) in your document
Key Takeaways
Four ways to render ∬ in HTML
∬ ∬ ∬For CSS stylesheets, use the escape in the content property
\222CUnicode U+222C — double integral over a region
Prefer ∬ for readability in HTML source
Single ∫ (∫) vs double ∬ (∬)
❓ Frequently Asked Questions
∬ (named), ∬ (hex), ∬ (decimal), or \222C in CSS content. All produce ∬.U+222C (DOUBLE INTEGRAL). Mathematical Operators block (U+2200–U+22FF). Hex 222C, decimal 8748. Used for double integrals over a region in the plane.∫, U+222B) integrates over one variable. Double integral (∬, ∬, U+222C) integrates over a region in the plane. Triple integral is U+222D (∭).∬ (capital I, then nt) is the named HTML entity for U+222C. It renders as ∬ and is the most readable option when writing HTML by hand.Explore More HTML Entities!
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