The n-ary summation ∑ means "add all of these together". Type 2211 then Alt+X in Word. It is a distinct character from Greek capital sigma at U+03A3, drawn taller and spaced as a large operator. Euler introduced the notation in 1755.
01 All shortcuts at a glance
| Platform | Shortcut | |
|---|---|---|
| Windows (any app) | Win+. or Win+; emoji/symbol picker, or Character Map (Win+R → charmap) |
|
| Mac | Control+Command+Space to open Character Viewer, search "N-Ary Summation" |
|
| Word / Outlook | Type 2211, then press Alt+X |
|
| Linux (IBus) | Ctrl+Shift+U, then 2211, then Enter |
|
| HTML / CSS | ∑ · \2211 (CSS) |
02 Step by step, per platform
A real, followable procedure for every platform, not a thin restatement of the shortcut.
Windows
- Open Character Map: Win+R, type charmap, press Enter.
- Search or scroll for N-Ary Summation (U+2211).
- Select it, click Copy, then paste where you need it.
Mac
- Press Control+Command+Space to open the Character Viewer.
- Type "N-Ary Summation" in the search field.
- Double-click the result to insert it.
Microsoft Word
- Type 2211.
- Press Alt+X immediately after, it converts the hex code to ∑.
03 Characters in this set
04 Troubleshooting & confusables
| Looks like it | But it's actually | When to use |
|---|---|---|
| Σ (U+03A3) | Greek capital sigma | For the Greek letter itself. Not for a summation in typeset mathematics. |
| ∏ (U+220F) | N-ary product | For multiplying a sequence rather than adding it. |
| E as a letter | The Latin capital E | Never. The summation sign has angled arms, not horizontal bars. |
05 FAQ
What is the Unicode code point for the summation sign?
It is U+2211, decimal 8721. Greek capital sigma is a separate character at U+03A3.
Should I use ∑ or Σ?
Use ∑ at U+2211 for a sum. It is taller and carries operator spacing. The Greek letter is what a Greek keyboard produces and means something different.
How do I read the notation?
The index and its start value sit below, the end value above, and the expression follows. It says to substitute each index value in turn and add the results.
What does an empty sum equal?
Zero, by convention, just as an empty product equals one. This keeps recursive and inductive definitions consistent at their base case.
How do I type it in Excel?
Excel uses the SUM function rather than the symbol, though the AutoSum button is drawn with it. The character itself can be inserted as text but will not calculate.