HTML Entity for Cube Root (∛)

Beginner

5 min read

Updated: Sep 2026

1 example

Unicode U+221B

HTML Entity for cube root (U+221B) tutorial illustration

Definition

What Is Cube Root?

Cube root (∛) is the Unicode character at U+221B in the Mathematical Operators block. It is a spacing radical for cube roots — for example ∛8 = 2.

Remember

Character     ∛
Unicode       U+221B
Hex entity    &#x221B;
Decimal       &#8731;
CSS escape    \221B
Named entity  (none for U+221B)
Not the same  √ U+221A · ∜ U+221C

Prefer typing ∛ in UTF-8 HTML when your editor supports it; use ∛ or ∛ when you need an explicit entity.

Reference

Quick Reference

One table for every form you will actually use.

Form	Code	Where it goes
Direct character	`∛`	HTML text (UTF-8)
Hex entity	`∛`	HTML markup
Decimal entity	`∛`	HTML markup
CSS escape	`\221B`	Stylesheet `content`
Square root	`√` / √ U+221A	Square-root radical — not cube root

When to Use Which

Situation	Use
Cube-root radical	`∛` or type `∛`
Square-root radical	√ U+221A (`√`)
Fourth-root radical	∜ U+221C
Generated / numeric-only markup	`∛` or `∛`
Generated text via `::before` / `::after`	`content: "\221B"`

See it

Live Preview

Cube root rendered in common math contexts.

Inline math ∛8 = 2

Large glyph ∛

Compared ∛ √ ∜

Monospace ∛x

With entities Hex: ∛ | Decimal: ∛

Code

Complete HTML Example

One page that shows Cube Root with hex, decimal, CSS escape, and a typed character. Use View Output or open the live editor.

Hex + Decimal + CSS + Typed

Four ways to produce ∛ in a single document.

html

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Cube Root (∛) in HTML</title>
  <style>
    #point::after {
      content: "\221B";
    }
  </style>
</head>
<body>
  <p>Cube root using Hex Code: &#x221B;</p>
  <p>Cube root using HTML Code: &#8731;</p>
  <p id="point">Cube root using CSS Entity: </p>
  <p>Typed directly: ∛</p>
</body>
</html>

Try It Yourself

How It Works

1. Hex: U+221B → ∛ in HTML → ∛.

2. Decimal: same code point as 8731 → ∛. Same result as hex.

3. CSS: use \221B in content (not an HTML entity). #point::after appends that ∛ after the paragraph text.

4. Typed: in a UTF-8 page you can paste ∛ directly. All four lines show the same glyph.

Pitfalls & Tips

Common mistakes when working with Cube Root.

Named?

No named entity

HTML5 has no &…; name for U+221B. Use ∛ or ∛. Do not use √ — that is square root.

√

Not square root

√ (√) is square root. ∛ is specifically cube root.

Layout

Plain text vs MathML

Unicode ∛ is fine for simple labels. For stacked radicals and indices, prefer MathML or a formula renderer.

CSS vs HTML

Do not mix escapes

\221B belongs in CSS strings. ∛ / ∛ belong in HTML.

Fonts

Math font coverage

Some fonts omit U+221B. Prefer a font with Mathematical Operators coverage for display.

Semicolon

End references

Always finish with ; — write ∛, not &#8731.

Compatibility

Browser Support

Cube root (U+221B) and its numeric entity forms (∛, ∛, CSS \\221B) are supported in all mainstream browsers. Visible glyphs depend on font coverage.

✓ Universal support

Cube Root (∛)

Encode with hex, decimal, CSS escape, or type the character — same code point everywhere encoding is supported.

100% Browser coverage

Google Chrome Supported

Yes

Microsoft Edge Supported

Yes

Mozilla Firefox Supported

Yes

Apple Safari Supported

Yes

Opera Supported

Yes

Internet Explorer All versions

Yes

U+221B / entities Full support

Bottom line: Use ∛ or ∛ in HTML when you need this radical, and \\221B only inside CSS content. Do not confuse with √ (square root).

Remember

Key Takeaways

Unicode: cube root is U+221B (decimal 8731) — glyph ∛.
HTML: type ∛, or use ∛ / ∛ (no named entity).
CSS: use \221B inside content for generated text.
Watch out: ∛ ≠ √ ≠ ∜ (cube ≠ square ≠ fourth root).

One line: U+221B → ∛ / ∛ / CSS \221B / type ∛.

Frequently Asked Questions

How do I display cube root (∛) in HTML?

Use ∛ (hex), ∛ (decimal), type ∛ directly in UTF-8, or the CSS escape \221B in content. There is no named HTML entity for U+221B.

What is the Unicode value for cube root?

U+221B (hex 221B, decimal 8731). It belongs to the Mathematical Operators block and is the cube-root radical symbol.

Is there a named HTML entity for U+221B?

No. Use numeric references like ∛ or ∛, or type the character ∛ in a UTF-8 document. Square root uses √ (U+221A) — that name is not for cube root.

When should I use U+221B?

Use it in math, algebra, or education pages that need a cube-root radical. For complex formulas, MathML or LaTeX may be clearer than plain Unicode.

What is the difference between HTML code and CSS entity for U+221B?

HTML entities (∛ or ∛) go in markup. The CSS escape \221B goes in stylesheet strings (usually content on ::before/::after).

How is ∛ different from √ and ∜?

∛ (U+221B) is cube root. √ (U+221A / √) is square root. ∜ (U+221C) is fourth root. They are different radical operators.

Did you know?

Cube root is Unicode U+221B (decimal 8731) — glyph ∛ in the Mathematical Operators block. HTML5 has no named entity. It is a spacing radical for cube roots (e.g. ∛8 = 2). It is not square root √ (U+221A / √) and not fourth root ∜ (U+221C).

Next: Curly Logical AND

Learn the HTML entity for curly logical AND (U+22CF).

Curly Logical AND tutorial →

About the author

Mari Selvan M P 🔗

Developer, cloud engineer, and technical writer

Experience 12 years building web and cloud systems
Focus Full Stack Development, AWS, and Developer Education

I write practical tutorials so students and working developers can learn by doing—from databases and APIs to deployment on AWS.

AWS Certified Developer – Associate (Credly)

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