HTML Entity for Uppercase R Double Struck Capital (ℝ)

Beginner

5 min read

Updated: Sep 2026

1 example

Unicode U+211D

HTML Entity for Uppercase R Double Struck Capital (U+211D) tutorial illustration

Definition

What Is the Uppercase R Double Struck Capital Entity?

Uppercase R Double Struck Capital (ℝ) is the Unicode character at U+211D (DOUBLE-STRUCK CAPITAL R) in Letterlike Symbols. It is the blackboard-bold capital R commonly used for the set of real numbers.

Remember

Character     ℝ
Unicode       U+211D
Hex entity    &#x211D;
Decimal       &#8477;
Named         &Ropf;  &reals;
CSS escape    \211D
Official name DOUBLE-STRUCK CAPITAL R

All of these produce the same glyph: ℝ. Compare with ordinary Uppercase R (U+0052) and &real; (U+211C, ℜ).

Reference

Quick Reference

One table for every form you will actually use.

Form	Code	Where it goes
Direct character	`ℝ`	HTML text (UTF-8)
Named entities	`&Ropf;` `&reals;`	HTML markup — preferred for readability
Hex entity	`ℝ`	HTML markup
Decimal entity	`ℝ`	HTML markup
CSS escape	`\211D`	Stylesheet `content`

When to Use Which

Situation	Use
Readable math / real-numbers set	`&Ropf;` or `&reals;`
Need numeric form	`ℝ` or `ℝ`
Generated text via `::before` / `::after`	`content: "\211D"`
Real part (black-letter R)	`&real;` (U+211C) — not this character
Ordinary capital letter R	Use R (U+0052)

See it

Live Preview

Double-struck capital R in common math contexts.

Large glyph ℝ

Real set x ∈ ℝ

Compared R ℝ ℜ

Named entities &Ropf; → ℝ &reals; → ℝ

With entities Hex: ℝ | Decimal: ℝ

Code

Complete HTML Example

One page that shows this character with hex, decimal, named entities, CSS, and a math sample. Use View Output or open the live editor.

Hex + Decimal + Named + CSS

All common ways to produce ℝ in a single document.

html

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Uppercase R Double Struck Capital</title>
  <style>
    #point::after {
      content: "\211D";
    }
  </style>
</head>
<body>
  <p>Using Hex Code: &#x211D;</p>
  <p>Using HTML Code: &#8477;</p>
  <p>Using Named Entity: &Ropf;</p>
  <p id="point">Using CSS Entity: </p>
  <p>x &isin; &reals;</p>
</body>
</html>

Try It Yourself

How It Works

1. Hex / decimal: U+211D → ℝ or ℝ in HTML.

2. Named: &Ropf; and &reals; are HTML5 aliases for the same code point.

3. CSS: use \211D in content (not an HTML entity). #point::after appends that glyph after the paragraph text.

4. Math sample: ∈ is ∈; together with &reals; it shows “x belongs to ℝ”.

Pitfalls & Tips

Common mistakes when working with this character.

Named

Prefer `&Ropf;` or `&reals;`

&Ropf; and &reals; are aliases. Prefer &reals; when meaning the real set; &Ropf; is shorter.

Look-alikes

`&reals;` ≠ `&real;`

&reals; → ℝ (U+211D). &real; → ℜ (U+211C, black-letter R). Easy to mistype.

Semantics

Prefer the letterlike symbol

Prefer U+211D over styling a plain R with a double-struck font when the semantics require the letterlike symbol.

Fonts

Check Letterlike coverage

Some fonts omit U+211D. Prefer fonts with good Letterlike Symbols / math support.

CSS vs HTML

Do not mix escapes

\211D belongs in CSS. Named/numeric entities belong in HTML.

Semicolon

End references

Always finish with ; — write &Ropf;, not &Ropf.

Compatibility

Browser Support

Uppercase R Double Struck Capital / DOUBLE-STRUCK CAPITAL R (U+211D) and its entity forms (&Ropf;, &reals;, ℝ, ℝ, CSS \\211D) are supported in all mainstream browsers. Glyph shape depends on the font.

✓ Universal support

Uppercase R Double Struck Capital

Encode with named, hex, decimal, or CSS escape — or paste the character in UTF-8 HTML.

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+211D / entities Full support

Bottom line: Prefer &Ropf; or &reals; for readable markup; use \\211D only inside CSS content. Do not confuse with &real; (ℜ).

Remember

Key Takeaways

Unicode: this character is U+211D (decimal 8477) — DOUBLE-STRUCK CAPITAL R.
HTML: prefer &Ropf; / &reals;, or use ℝ / ℝ.
CSS: use \211D inside content for generated text.
Watch out: &reals; (ℝ) ≠ &real; (ℜ) ≠ plain R.

One line: U+211D → &Ropf; / &reals; / ℝ / CSS \211D.

Frequently Asked Questions

How do I display Uppercase R Double Struck Capital in HTML?

Use &Ropf; or &reals; (named), ℝ (hex), ℝ (decimal), or the CSS escape \211D in the content property. All render U+211D.

What is the Unicode value for Uppercase R Double Struck Capital?

U+211D (hex 211D, decimal 8477). Unicode names it DOUBLE-STRUCK CAPITAL R. It belongs to Letterlike Symbols and commonly denotes the set of real numbers.

Is there a named HTML entity for U+211D?

Yes. HTML5 defines &Ropf; and &reals; — both map to U+211D. Prefer &reals; when meaning the real-numbers set; &Ropf; is shorter.

How is &reals; different from &real;?

&reals; is U+211D (ℝ, double-struck R). &real; is U+211C (ℜ, black-letter capital R), often used for the real part of a complex number. They are different characters.

When should I use this character?

Use it in mathematical text for the real numbers set (ℝ), set theory, or other double-struck notation. Prefer &Ropf; or &reals; for readable markup.

What is the difference between HTML code and CSS entity for U+211D?

HTML entities (&Ropf;, ℝ, or ℝ) go in markup. The CSS escape \211D is used in stylesheets (usually in the content property of ::before/::after). Both render the same glyph.

Did you know?

This character is Unicode U+211D (decimal 8477) — official name DOUBLE-STRUCK CAPITAL R in Letterlike Symbols. HTML5 defines &Ropf; and &reals;. In mathematics it commonly denotes the set of real numbers ℝ. Do not confuse with &real; (U+211C, black-letter ℜ).

Next: Uppercase R Inverted Breve

Learn the HTML entity for Uppercase R Inverted Breve — next in this sequence.

Continue tutorial →

About the author

Mari Selvan M P 🔗

Developer, cloud engineer, and technical writer

Experience 12 years building web and cloud systems
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I write practical tutorials so students and working developers can learn by doing—from databases and APIs to deployment on AWS.

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