HTML Entity for Planck Constant (ℎ)

Beginner
⏱️ 5 min read
📚 Updated: Jun 2026
🎯 1 Code Example
Unicode U+210E
HTML Entity for Planck constant symbol tutorial illustration

What You'll Learn

How to display the Planck constant symbol (ℎ) in HTML using various entity methods. This character represents h in physics notation—Planck’s constant—and is essential for quantum mechanics, physics articles, and scientific documentation.

This character is part of the Letterlike Symbols Unicode block and can be rendered with a hexadecimal reference, a decimal reference, the named entity ℎ, or a CSS escape in the content property. Do not confuse ℎ with U+210F (ℏ, reduced Planck constant h-bar) or ordinary Latin h (U+0068).

⚡ Quick Reference — Planck Constant Entity

Unicode U+210E

Letterlike Symbols block

Hex Code ℎ

Hexadecimal reference

HTML Code ℎ

Decimal reference

Named Entity ℎ

Most readable option

Reference Table
Name           Value
────────────   ──────────
Unicode        U+210E
Hex code       ℎ
HTML code      ℎ
Named entity   ℎ
CSS code       \210E
Meaning        Planck constant (h)
Related        U+210F = Planck constant over two pi (ℏ)
               U+0068 = Latin small letter h (h)
Block          Letterlike Symbols (U+2100–U+214F)
1

Complete HTML Example

A simple example showing ℎ using hexadecimal code, decimal HTML code, the named entity, and a CSS content escape:

html
<!DOCTYPE html>
<html>
<head>
 <style>
  #point::after{
   content: "\210E";
  }
 </style>
</head>
<body>
<p>Planck constant (hex): &#x210E;</p>
<p>Planck constant (decimal): &#8462;</p>
<p>Planck constant (named): &planckh;</p>
<p id="point">Planck constant (CSS): </p>
</body>
</html>
Try it Yourself

🌐 Browser Support

The Planck constant entity is universally supported in all modern browsers:

Chrome 1+
Firefox 1+
Safari 1+
Edge 12+
Opera 4+
Android 4.4+
iOS Safari 1+

👀 Live Preview

See the Planck constant symbol rendered live in different contexts:

Inline text Planck’s constant h = 6.626 × 10−34 J·s (symbol: ℎ)
Large glyph ℎ
In a formula E = ℎf
Not the same as h-bar ℏ  |  Latin h  |  Greek η
Entity refs &#x210E; &#8462; &planckh; \210E

🧠 How It Works

1

Hexadecimal Code

&#x210E; uses the Unicode hexadecimal value 210E to display the Planck constant symbol. The x prefix indicates hexadecimal format.

HTML markup
2

Decimal HTML Code

&#8462; uses the decimal Unicode value 8462 to display the same character. This is one of the most commonly used methods.

HTML markup
3

CSS Entity

\210E is used in CSS stylesheets, particularly in the content property of pseudo-elements like ::before and ::after.

CSS stylesheet
4

Named Entity

&planckh; is the semantic named entity — the easiest to read in source HTML and the most self-descriptive option for Planck’s constant h.

HTML markup
=

Same visual result

All four methods produce the Planck constant glyph: ℎ. Unicode U+210E sits in the Letterlike Symbols block (U+2100–U+214F). For h-bar use U+210F (ℏ).

✅

Use Cases

The Planck constant symbol (ℎ) commonly appears in the following scenarios:

⚛ Quantum Physics

Quantum mechanics articles referencing Planck’s constant h.

📄 Research Papers

Academic publications, preprints, and physics journals on the web.

🎓 Education

Physics textbooks, lecture notes, and online courses for students.

💻 Science Blogs

Popular science articles explaining energy quanta and photon energy E = hf.

📋 Reference Tables

Unicode and HTML entity guides for physics symbols.

📝 Technical Docs

Scientific software documentation and physics simulation guides.

♿ Accessibility

Pair ℎ with “Planck’s constant” or “h” on first use in educational content.

💡 Best Practices

Do

  • Use &planckh; for readable physics markup
  • Distinguish ℎ (h) from ℏ (h-bar) in quantum content
  • Pick one style (hex / decimal / named) per project
  • Use MathML or LaTeX for complex multi-line equations when appropriate
  • Test the glyph across browsers and scientific fonts

Don’t

  • Confuse ℎ (Planck constant h) with ℏ (reduced constant, h-bar)
  • Use &planck; for h—that entity is for U+210F (ℏ)
  • Substitute ordinary Latin h when semantic Planck notation is required
  • Use CSS escape \210E inside HTML text nodes
  • Use HTML entities in JS (use \u210E instead)

Key Takeaways

1

Three HTML references all render ℎ

&#x210E; &#8462; &planckh;
2

For CSS stylesheets, use the escape in the content property

\210E
3

Unicode U+210E belongs to the Letterlike Symbols block (U+2100–U+214F)

4

For h-bar (ℏ), use &planck; on the modified Planck constant page

5

Previous: Pitchfork (⋔)   Next: Planck Constant Over Two Pi (ℏ)

❓ Frequently Asked Questions

Use &#x210E; (hex), &#8462; (decimal), &planckh; (named), or \210E in CSS content. All produce ℎ.
U+210E (PLANCK CONSTANT). Letterlike Symbols block. Hex 210E, decimal 8462. Denotes Planck’s constant h in physics notation.
No. ℎ (U+210E) is Planck’s constant h. ℏ (U+210F) is the reduced Planck constant (h-bar, often written ℏ or ħ). Use &planckh; for h and &planck; for ℏ.
In physics articles, quantum mechanics documentation, scientific textbooks, research papers, educational content, and any web page referencing Planck’s constant h.
Yes. &planckh;, &#8462;, and &#x210E; are equivalent in modern browsers and all render ℎ.

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About the author

Mari Selvan M P
Mari Selvan M P 🔗

Developer, cloud engineer, and technical writer

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Pitchfork (⋔) Planck Constant Over Two Pi (ℏ)