HTML Entity for Sigma (Σ)

Beginner

5 min read

Updated: Sep 2026

1 example

Unicode U+03A3

HTML Entity for Sigma (U+03A3) tutorial illustration

Definition

What Is the Sigma Entity?

Sigma (Σ) is the Greek and Coptic character at Unicode U+03A3 (GREEK CAPITAL LETTER SIGMA). HTML5 names it Σ. Use it for Greek capital sigma in math, statistics, and scientific text.

Remember

Character     Σ
Unicode       U+03A3
Named entity  &Sigma;
Hex entity    &#x03A3;
Decimal       &#931;
CSS escape    \03A3
Not the same  &sigma; (σ) · &sum; (∑)

Named, hex, decimal, CSS, and a typed character all produce the same glyph: Σ. Prefer Σ in HTML markup. For indexed summation, see N-Ary Summation (∑).

Reference

Quick Reference

One table for every form you will actually use.

Form	Code	Where it goes
Named entity	`Σ`	HTML markup (best default)
Hex entity	`Σ`	HTML markup
Decimal entity	`Σ`	HTML markup
CSS escape	`\03A3`	Stylesheet `content`
Direct character	`Σ`	UTF-8 HTML text

When to Use Which

Situation	Use
Greek capital sigma	`Σ` (preferred)
Numeric-only markup	`Σ` or `Σ`
Generated text via `::before` / `::after`	`content: "\03A3"`
Greek small sigma	Use `σ` (U+03C3, σ) — case matters
N-ary summation operator	Use ∑ (U+2211)

See it

Live Preview

Greek capital Sigma in stats and Greek contexts, compared with look-alikes.

Statistics Σ = population standard deviation

Large glyph Σ

Named entity Σ → Σ

vs small / sum Σ | σ | ∑

With entities Named: Σ | Hex: Σ | Decimal: Σ

Code

Complete HTML Example

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

Named + Hex + Decimal + CSS + Typed

Five ways to display Σ in HTML and CSS.

html

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Sigma (Σ)</title>
  <style>
    #point::after {
      content: "\03A3";
    }
  </style>
</head>
<body>
  <p>Built with Named: &Sigma;</p>
  <p>Built with Hex: &#x03A3;</p>
  <p>Built with Decimal: &#931;</p>
  <p id="point">Built with CSS: </p>
  <p>Typed: Σ</p>
  <p>Stats: &Sigma; = population std. dev.</p>
</body>
</html>

Try It Yourself

How It Works

1. Named: Σ is the preferred HTML5 name for U+03A3 → Σ.

2. Hex: Σ inserts the same code point. Same visual as named.

3. Decimal: same code point as 931 → Σ.

4. CSS: use \03A3 in content (not an HTML entity). #point::after appends Σ.

5. Typed: paste Σ in a UTF-8 document, or write labels like Σ = ….

Pitfalls & Tips

Common mistakes when working with Sigma.

Named

Prefer `Σ`

Σ is the clear HTML5 named form. It is case-sensitive — write Σ, not &SIGMA;. σ is lowercase (U+03C3).

Look-alikes

Σ ≠ σ ≠ ∑

U+03A3 is capital sigma. U+03C3 is small sigma. U+2211 is n-ary summation (∑) — use that for Σ-style sums in equations.

A11y

Add context

A lone Σ may be unclear. Pair it with text (e.g. “population standard deviation”) or an accessible name.

CSS vs HTML

Do not mix escapes

\03A3 belongs in CSS. Σ / Σ / Σ belong in HTML.

Semicolon

End references

Always finish with ; — write Σ, not &Sigma.

Fonts

Greek coverage

Most modern fonts include Greek capital sigma. Still test math pages on mobile if you mix Greek and Latin scripts.

Compatibility

Browser Support

Sigma (U+03A3) and its entity forms (Σ, Σ, Σ, CSS \\03A3) are supported in all modern browsers. Glyph coverage depends on the font.

✓ Universal encoding

Sigma (Σ)

Encode with named, hex, decimal, or CSS escape — or type Σ directly in UTF-8 HTML. Prefer Σ.

100% Browser coverage

Google Chrome Supported

Yes

Microsoft Edge Supported

Yes

Mozilla Firefox Supported

Yes

Apple Safari Supported

Yes

Opera Supported

Yes

Internet Explorer IE 9+

Yes*

U+03A3 Full support

Bottom line: Prefer Σ for readable HTML. Use \\03A3 only inside CSS content. Use ∑ for n-ary summation.

Remember

Key Takeaways

Unicode: this symbol is U+03A3 (decimal 931) — Greek capital letter sigma.
HTML: prefer Σ — or use Σ / Σ.
CSS: use \03A3 inside content for generated Greek letters.
Watch out: not the same as σ (lowercase) or ∑ (n-ary summation).

One line: U+03A3 → Σ / Σ / Σ / CSS \03A3.

Frequently Asked Questions

How do I display Sigma (Σ) in HTML using entities?

Use Σ (named), Σ (hex), Σ (decimal), or the CSS escape \03A3 in the content property. All render Σ. Prefer Σ for readable markup.

What is the Unicode value for Sigma?

U+03A3 (GREEK CAPITAL LETTER SIGMA). Hex 03A3, decimal 931, named entity Σ. It belongs to Greek and Coptic (U+0370–U+03FF).

Is there a named HTML entity for U+03A3?

Yes. HTML5 defines Σ for U+03A3. It is case-sensitive — write Σ, not &SIGMA;. Lowercase σ is a different character (U+03C3).

Is Σ the same as the summation symbol (∑)?

No. U+03A3 (Σ) is the Greek capital letter sigma. U+2211 (∑) is N-ARY SUMMATION with named entity ∑. Use ∑ for indexed summation in equations.

When should I use this HTML entity?

Use it for Greek capital sigma in math, statistics (e.g. population standard deviation), Greek text, and scientific notation. Prefer Σ in source for clarity.

What is the difference between HTML code and CSS entity for U+03A3?

HTML entities (Σ, Σ, or Σ) go in markup. The CSS escape \03A3 is used in stylesheets (usually in the content property of ::before/::after). Both render Σ.

Did you know?

Sigma is Unicode U+03A3 (decimal 931) — glyph Σ (GREEK CAPITAL LETTER SIGMA) in Greek and Coptic. HTML5 names it Σ (case-sensitive). Prefer it for Greek letters and statistics. Do not confuse it with N-Ary Summation (∑, U+2211) or lowercase sigma (σ, U+03C3).

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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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