The sigma symbol is Σ. On Windows, hold Alt and type 931 on the numeric keypad inside any Unicode-aware app; in Word, type 03A3 and press Alt+X. On Mac there is no Option shortcut, so open Character Viewer with Ctrl+Cmd+Space and search “sigma.” Both give the Greek capital letter sigma.
Sigma has no code-page Alt code in the modern Western set, which trips up a lot of guides. The methods below are the ones that actually produce Σ, sorted so the fastest for your app is near the top. The reference table has every code in one place.
Sigma symbol quick reference
| Method | Input | Works in |
|---|---|---|
| Windows Alt code (decimal) | 03A3 then Alt+X in Word | Unicode-aware apps only |
| Legacy Alt code (CP437) | Alt+0228 | Old DOS-era code page apps |
| Word Alt+X | 03A3, then Alt+X | Word, Outlook, OneNote |
| Mac | Character Viewer (no shortcut) | Most Mac apps |
| Excel / Google Sheets | =UNICHAR(931) | Spreadsheet cells |
| Chromebook / Linux | Ctrl+Shift+U, then 03a3 | ChromeOS, Linux |
| HTML (named) | Σ | Web pages |
| HTML (numeric) | Σ or Σ | Web pages |
| CSS escape | \03A3 | Stylesheets, content property |
| LaTeX | \Sigma | Math typesetting |
| Unicode code point (hex) | U+03A3 | Universal reference |
One thing to keep straight before you start: Alt codes take a decimal number (931), while Word’s Alt+X, the Chromebook shortcut, and CSS all take the hex value (03A3). They point to the same character but are not interchangeable. Typing 03A3 then Alt+X in Word gives you nothing.
Type the sigma symbol on Windows
There is no CP1252 Alt code for Σ, so the usual leading-zero form does not exist here. What works is the plain decimal code in apps that understand Unicode.
- Turn Num Lock on.
- Hold the left Alt key.
- Type 931 on the numeric keypad, not the top-row number keys.
- Release Alt.
This needs a real numeric keypad, and it only lands in Unicode-aware apps such as Word, WordPad, and browser fields. On a laptop with no keypad, use the on-screen options in the Alt code finder tool or Character Map instead.
You may see Alt+0228 listed elsewhere for sigma. That code reads from the machine’s OEM code page: it maps to Σ under CP437 (the US default) but can produce a different character under CP850, which is the default in the UK, Ireland, Canada, and Australia. Skip it for anything that has to be portable.
If neither route fits, open Character Map (search “charmap”), pick a font, find Σ, and copy it. The emoji panel (Win+.) does not reliably list Greek letters, so Character Map is the better picker on Windows.
Type the sigma symbol on Mac
Mac has no Alt codes and no Option shortcut for capital sigma. Use Character Viewer.
- Press Ctrl+Cmd+Space to open Character Viewer.
- Type “sigma” in the search box.
- Double-click Σ to insert it, or drag it into your document.
Character Viewer keeps recently used characters at the top, so after the first time sigma is one click away. This works in Pages, Numbers, Keynote, Mail, and most other Mac apps.
Type sigma in Word, Outlook, and PowerPoint
Word has the cleanest method: the hex-to-glyph shortcut. Type 03A3, then press Alt+X, and the four characters flip to Σ.
Reverse it by putting the cursor after Σ and pressing Alt+X again. This also works in Outlook and OneNote.
Prefer a menu? Go to Insert → Symbol → More Symbols, set the subset to Greek and Coptic, and pick Σ.
The exact same Insert → Symbol route works in PowerPoint, which has no Alt+X support of its own. You can also set up an AutoCorrect entry in Word (for example, replace \Sigma with Σ) if you type it often.
Type sigma in Excel and Google Sheets
Spreadsheets do not use Alt+X, so reach for a formula. In both Excel and Google Sheets, =UNICHAR(931) returns Σ. Wrap it in text with the ampersand operator, like ="Total "&UNICHAR(931), when you need the symbol inside a label.
Google Sheets has no Insert Symbol menu at all, despite what some pages claim. If you want to use an OS-level input method inside a cell, press F2 first to enter edit mode, then type or paste. Otherwise the formula is the reliable path.
Type sigma in Google Docs
Docs has a proper picker. Open Insert → Special characters, then either type “sigma” in the search box or draw the shape in the sketch pad on the right.
Click Σ to drop it at the cursor. Google Docs remembers recent characters, so repeat inserts are quick.
Type sigma on iPhone and Android
Neither phone keyboard has a sigma key by default. The most durable fix is a Greek keyboard: on iPhone add it under Settings → General → Keyboard → Keyboards; on Android add Greek in your keyboard’s language settings, then switch layouts and type capital sigma directly.
If you only need it occasionally, copy Σ from the button above and paste it. To make it permanent, set a text replacement (iPhone: Settings → General → Keyboard → Text Replacement; Android: your keyboard’s personal dictionary) so a shortcut like “sig” expands to Σ.
Type sigma on a Chromebook
ChromeOS has no Alt codes, and adding a USB numpad will not change that, because the feature is Windows software, not hardware. Use the Unicode input shortcut instead.
- Press Ctrl+Shift+U. An underlined u appears.
- Type 03a3 (the hex value, no U+ prefix).
- Press Enter or Space to confirm.
Some web text fields swallow the shortcut. When that happens, open the symbol picker with Launcher+Shift+Space (newer Chromebooks have a dedicated Quick Insert key) or just paste Σ.
Sigma in Notion, Slack, Discord, and Canva
None of these has a built-in sigma shortcut. The reliable move everywhere is to paste Σ from the copy button. For anything you type regularly, lean on a text replacement so the symbol is always a few keystrokes away.
Notion accepts pasted characters anywhere and inside its inline equation blocks (type /equation, then \Sigma). Slack and Discord have no sigma emoji, so paste it into the message box. Canva takes pasted text into any text box; set the font first, since sigma renders differently across typefaces.
Sigma in HTML and CSS
On the web, use the named entity Σ for readability, or the numeric forms Σ (decimal) and Σ (hex, note the x). In CSS, the escape is \03A3, which is what you write inside a content property. All three render the same Greek capital letter sigma.
When sigma does not show up right
The most common mix-up is sigma versus the summation sign. Σ is the Greek letter.
The math operator you stretch over a formula is a separate character, the n-ary summation sign, which is taller and built for equations. If your totals look slightly off in a technical document, you probably used the letter where the operator belonged.
If Σ shows as a box (□) or a question mark, the font lacks the glyph. Some display and icon fonts skip Greek entirely. Switch to a broad text font such as Arial, Calibri, Times New Roman, or a system UI font, and the character reappears without changing the underlying code.
Where sigma is actually used
Capital sigma marks summation in math and stats: the running total of a series. It also names sigma bonds in chemistry and appears in engineering notation and set theory. In branding and stylized text it stands in for a capital E, which is why it turns up in logos and usernames.
Related Greek and math symbols
Sigma sits in a cluster of Greek letters people reach for in the same formulas, and it is easy to grab the wrong one.
- Type the omega symbol (Ω) — the last Greek letter, used for ohms in electronics.
- Type the delta symbol (Δ) — the triangle that means change or difference.
- Type the pi symbol (π) — the circle constant, and a product operator in its capital form.
- Type the phi symbol (φ), the golden-ratio letter, easy to confuse with a slashed zero.
Frequently asked questions
What is the difference between Σ and the summation sign?
Σ is the Greek capital letter sigma, meant to be read as a letter. The summation sign in math is a different, taller Unicode character built as an operator. For real equations, use the summation operator; for the letter itself, use Σ.
How do I type lowercase sigma?
Lowercase sigma (σ) and its word-final form (ς) are separate characters from the capital. The quickest way to get them is a Greek keyboard layout, or Character Viewer on Mac and Character Map on Windows. Search “sigma” in either picker and both cases appear.
Why does Alt+0228 give a different symbol on my computer?
Zero-less Alt codes read from your machine’s OEM code page. Under CP437 (US default) Alt+0228 maps to Σ, but under CP850 (UK, Ireland, Canada, Australia) it maps to something else. Use 03A3 then Alt+X in Word in a Unicode-aware app for a result that does not depend on region.
Can I type sigma without a numeric keypad?
Yes. The 03A3 then Alt+X in Word route is the only method that needs the keypad.
Word’s Alt+X, Character Map, Google Docs special characters, and simple paste all work without one. The Alt code finder also lets you click the character directly.
Why won’t 03A3 then Alt+X in Word work in Notepad or my chat app?
The decimal Alt code only fires in apps that handle Unicode input this way, and some lightweight editors and chat boxes do not. When it produces nothing, paste the symbol instead, or set a text replacement so a short trigger expands to Σ.
Keep exploring symbols
For more formula-ready characters, browse the math and science symbol guides. If you work with codes often, the full Alt code list collects every verified value in one place, and the degree Fahrenheit symbol guide (℉) covers another character with no simple Alt code and the same keypad-free workarounds.