HTML Entity for Planck Constant Over Two Pi (ℏ)

Beginner
⏱️ 5 min read
📚 Updated: Jun 2026
🎯 1 Code Example
Unicode U+210F
HTML Entity for reduced Planck constant (h-bar, U+210F) tutorial illustration

What You'll Learn

How to display the reduced Planck constant (ℏ, h-bar) in HTML using various entity methods. This character represents ħ (h divided by 2π) in quantum mechanics—the symbol physicists call h-bar—and is essential for wave functions, angular momentum, and quantum physics notation.

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

⚡ Quick Reference — Planck Constant Over Two Pi

Unicode U+210F

Letterlike Symbols block

Hex Code ℏ

Hexadecimal reference

HTML Code ℏ

Decimal reference

Named Entity ℏ

Most readable option

Reference Table
Name           Value
────────────   ──────────
Unicode        U+210F
Hex code       ℏ
HTML code      ℏ
Named entity   ℏ
CSS code       \210F
Meaning        Planck constant over two pi (h-bar)
Also written   ħ = h / 2π
Related        U+210E = Planck constant h (ℎ)
               U+0068 = Latin small letter h (h)
Block          Letterlike Symbols (U+2100–U+214F)
1

Complete HTML Example

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

html
<!DOCTYPE html>
<html>
<head>
 <style>
  #point::after{
   content: "\210F";
  }
 </style>
</head>
<body>
<p>h-bar (hex): &#x210F;</p>
<p>h-bar (decimal): &#8463;</p>
<p>h-bar (named): &planck;</p>
<p id="point">h-bar (CSS): </p>
</body>
</html>
Try it Yourself

🌐 Browser Support

The reduced 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 h-bar (ℏ) rendered live in different contexts:

Inline text The reduced Planck constant ℏ = 1.055 × 10−34 J·s
Large glyph ℏ
In a formula E = ℏω
Not the same as Planck h ℎ  |  Latin h  |  Greek η
Entity refs &#x210F; &#8463; &planck; \210F

🧠 How It Works

1

Hexadecimal Code

&#x210F; uses the Unicode hexadecimal value 210F to display h-bar. The x prefix indicates hexadecimal format.

HTML markup
2

Decimal HTML Code

&#8463; uses the decimal Unicode value 8463 to display the same character. This is one of the most commonly used methods.

HTML markup
3

CSS Entity

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

CSS stylesheet
4

Named Entity

&planck; is the semantic named entity — the easiest to read in source HTML for the reduced Planck constant symbol.

HTML markup
=

Same visual result

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

✅

Use Cases

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

⚛ Quantum Mechanics

Wave functions, Schrödinger equation, and ℏ in quantum formulas.

📄 Research Papers

Physics preprints, journal articles, and academic publications online.

🎓 Education

University physics courses, textbooks, and lecture notes on quantum theory.

💻 Science Blogs

Popular science articles explaining angular momentum and energy quanta.

📋 Reference Tables

Unicode and HTML entity guides for physics and Letterlike Symbols.

📝 Technical Docs

Scientific software, simulation tools, and physics API documentation.

♿ Accessibility

Pair ℏ with “h-bar” or “reduced Planck constant” on first use.

💡 Best Practices

Do

  • Use &planck; for readable h-bar markup
  • Distinguish ℏ (h-bar) from ℎ (Planck constant h)
  • 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

  • Use &planckh; for h-bar—that entity is for U+210E (ℎ)
  • Confuse ℏ with ordinary Latin h or Greek η
  • Call it “modified Planck constant” without explaining it means h-bar (ℏ = h/2π)
  • Use CSS escape \210F inside HTML text nodes
  • Use HTML entities in JS (use \u210F instead)

Key Takeaways

1

Three HTML references all render ℏ

&#x210F; &#8463; &planck;
2

For CSS stylesheets, use the escape in the content property

\210F
3

Unicode U+210F — PLANCK CONSTANT OVER TWO PI (h-bar)

4

For Planck’s constant h (ℎ), use &planckh; on the Planck constant page

5

Previous: Planck Constant (ℎ)   Next: Plus (+)

❓ Frequently Asked Questions

Use &#x210F; (hex), &#8463; (decimal), &planck; (named), or \210F in CSS content. All produce ℏ.
U+210F (PLANCK CONSTANT OVER TWO PI). Letterlike Symbols block. Hex 210F, decimal 8463. Denotes h-bar: ℏ = h/2π.
No. ℎ (U+210E) is Planck’s constant h. ℏ (U+210F) is the reduced Planck constant (h-bar, ħ = h/2π). Use &planckh; for h and &planck; for ℏ.
In quantum mechanics articles, wave-function notation, angular momentum formulas, physics textbooks, research papers, and any content referencing ħ (h-bar).
Yes. &planck;, &#8463;, and &#x210F; are equivalent in modern browsers and all render ℏ.

Explore More HTML Entities!

Discover 1500+ HTML character references — currency symbols, arrows, math operators, emojis, and more.

All HTML Entities →

About the author

Mari Selvan M P
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)

8 people found this page helpful

Planck Constant (ℎ) Plus (+)