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Sigma Symbol (Σ)

The sigma symbol (Σ) is the Greek capital sigma — in maths it means 'add them all up' (summation), and its lowercase σ is the standard deviation symbol.

Greek Capital Letter Sigma · U+03A3 · Greek Letters

Click the symbol or the button to copy it, then paste it anywhere — documents, messages, bios and code.

Sigma Symbol codes

Code	Value
Unicode code point	`U+03A3`
Unicode name	`Greek Capital Letter Sigma`
HTML named entity	`Σ`
HTML decimal	`Σ`
HTML hex	`Σ`
CSS content code	`\3A3`
JavaScript / JSON	`\u03A3`
Windows Alt code	No standard Alt code — copy it from the card above
LaTeX	`\Sigma`

Sigma Symbol variants (3)

3 related glyphs — click any tile to copy it. Tiles with a page open that symbol's own page.

σGreek Small Letter SigmaςGreek Small Letter Final Sigma∑N-Ary Summation

Meaning & usage

Σ does two famous jobs. As the summation operator, Σ tells you to add a whole series of numbers — the backbone of statistics, spreadsheets and algorithms.

Its lowercase form σ is the standard deviation symbol, measuring how spread out data is. The letter itself is the Greek S, which is why sigma lends its name to everything from Six Sigma quality programmes to the final letter in Greek words (ς).

Examples in use

Σx means 'the sum of all x values'
σ = 5 shows moderate spread in data
Six Sigma targets near-perfect quality

How to type the sigma symbol

Windows

There is no Alt code or direct key for Σ. In Microsoft Word, type 03A3 and press Alt+X to convert it. Everywhere else, click the Copy button at the top of this page and paste it (Ctrl+V) — that always works.

Mac

There is no Option-key shortcut for Σ on a Mac. Open the Character Viewer with Control+Command+Space, search for "Sigma Symbol", and double-click to insert — or copy it from this page.

iPhone & Android

Most phone keyboards have no built-in key for Σ. Open this page on your phone, tap Copy, then paste it into your message or bio. (On Android, Gboard's emoji search finds some symbols by name.)

Linux

Press Ctrl+Shift+U, type 03a3 and press Enter (works in most GTK apps and terminals with IBus). Or copy it from this page.

Frequently asked questions

What is the difference between Σ and σ?

Capital Σ is the summation operator ('add everything up') and a Greek capital letter. Lowercase σ is the standard deviation symbol in statistics and the ordinary Greek letter sigma.

How do I type Σ on a keyboard?

There is no standard Alt code. Copy it from this page, or in Word type 03A3 then press Alt+X.

Why does Σ sometimes show as a box or question mark?

The box (called tofu) means the device or font viewing it has no drawing for U+03A3 (Greek Capital Letter Sigma). The character itself is fine — try a different font or a newer device, or use one of the variants on this page.

Is the Sigma Symbol free to use?

Yes. Σ is a standard Unicode text character published in the Unicode Character Database. You may use it in personal and commercial documents, designs and products without permission or payment.