How to Type the Cube Root Symbol (∛) Fast

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The cube root symbol is ∛. In Microsoft Word, type 221B and press Alt+X and it flips into the glyph.

In Excel or Google Sheets, the formula =UNICHAR(8731) returns it. There is no standard Windows Alt code for the cube root symbol, so in most other apps the fastest move is to copy it and paste.

Cube root symbol quick reference

MethodInputWorks in
Windows Alt code (decimal)221B then Alt+X in WordUnicode-aware Windows apps only
Word / Outlook / OneNote221B, then Alt+XWord, Outlook, OneNote
Insert → SymbolCharacter code 221B (Unicode hex)Word, PowerPoint, Excel
Mac Character ViewerCtrl+Cmd+Space, search “cube root”Most Mac apps
Excel & Google Sheets=UNICHAR(8731)Excel, Google Sheets
Chromebook / LinuxCtrl+Shift+U then 221bChromeOS, Linux
HTML∛ or ∛Web pages
CSS\221BWeb pages
Unicode code pointU+221BEverywhere

Watch the number bases. Alt codes take the decimal value 8731, while Word’s Alt+X, the Chromebook shortcut, and CSS take the hexadecimal value 221B. They point at the same character, so don’t swap one for the other.

There is no leading-zero Alt+0xxx code for this glyph and no legacy CP437 code either, so 221B then Alt+X in Word is the only Alt-key route, and only some programs accept it.

Type the cube root symbol on Windows

Windows has no standard Alt code for this symbol, so the usual Alt+0xxx trick produces nothing. Two routes work instead: the decimal code in apps that read it, and Character Map everywhere else.

221B then Alt+X in Word in Unicode-aware apps

  1. Turn Num Lock on and use the numeric keypad. The number row along the top will not work for Alt codes.
  2. Hold Alt, type 8731, then release Alt.

This works in Unicode-aware programs such as WordPad. Many apps ignore decimal Unicode input, so if nothing appears, use Character Map or paste from the button above.

Character Map (works everywhere)

  1. Press Start, type Character Map, and open it.
  2. Tick Advanced view, type cube root in the search box, and click Search.
  3. Select ∛, click Copy, then paste it into your document.

Type it on a Mac

Macs have no Option shortcut for this sign and no Alt codes at all, so use the Character Viewer.

  1. Press Ctrl+Cmd+Space to open the Character Viewer.
  2. Type cube root in the search field.
  3. Double-click ∛ to drop it in at the cursor.

Click the star in the viewer to add ∛ to Favorites, and it sits at the top for next time.

Type it in Word and PowerPoint

Word’s Alt+X (fastest)

  1. Type 221B where you want the symbol.
  2. Press Alt+X. The code turns into ∛.

This works in Word, Outlook, and OneNote. It does not work in PowerPoint or Excel, so use the Insert menu there.

Insert → Symbol (Word and PowerPoint)

  1. Go to Insert → Symbol → More Symbols.
  2. Set the “from” box to Unicode (hex).
  3. Type 221B in the Character code box, then click Insert.

PowerPoint has no Alt+X, so this Insert → Symbol path is its main route. The same menu works in Word if you would rather click than type a code.

Type it in Excel and Google Sheets

Neither spreadsheet needs a symbol menu. Type =UNICHAR(8731) in a cell and press Enter, and it returns ∛. Excel also has Insert → Symbol (character code 221B in Unicode hex), but Google Sheets has no symbol menu, so the formula or a paste is your only route there.

To keep it as a fixed character instead of a formula result, copy the cell and choose Paste Special → Values. If you paste into a Sheets cell with an operating-system tool, press F2 first to enter edit mode.

Type it in Google Docs

Google Docs has a proper symbol picker, which Google Sheets lacks.

  1. Go to Insert → Special characters.
  2. Type cube root in the search box, or draw the shape in the sketch pad.
  3. Click ∛ to insert it at the cursor.

Type it on iPhone and Android

Neither phone keyboard hides ∛ under a long-press, so the quick fix is to paste it from the copy button above. If you use it often, set up a text shortcut and it types itself.

  • iPhone: Settings → General → Keyboard → Text Replacement → +. Paste ∛ in the Phrase field and type something like cbrt in the Shortcut field.
  • Android (Gboard): Settings → Dictionary → Personal dictionary → your language → +. Enter ∛ and a shortcut such as cbrt.

After that, typing cbrt expands to ∛ in any app on the phone.

Type it on a Chromebook

ChromeOS has no Alt codes, and plugging in a numeric keypad will not change that, because the feature is Windows software rather than keypad hardware. Use the Unicode input shortcut.

  1. Put the cursor where you want the symbol.
  2. Hold Ctrl+Shift+U. An underlined u appears.
  3. Type 221b (the hex code, no U+ prefix), then press Enter or Space.

Some web text fields swallow the shortcut. If nothing shows, open the symbol picker with Launcher+Shift+Space (the Quick Insert key on newer Chromebooks), or paste instead.

Type it in Notion, Slack, Discord, and Canva

None of these apps has a built-in shortcut for the cube root sign, so paste it from the copy button. The one setup that fixes all of them at once is an operating-system text replacement: the phone shortcut above, or Text Replacements under System Settings → Keyboard on a Mac. It fires inside every app you type in.

In Canva, add a text box and paste ∛. If it shows as a box, switch to a font with broad coverage such as Arial or a Noto family.

Type it in HTML and CSS

The cube root symbol has no named HTML entity, so use a numeric reference. Both forms produce ∛.

  • HTML, decimal: ∛
  • HTML, hex: ∛
  • CSS content: content: "\221B";

Set the element in a font with math coverage, such as Cambria Math, Segoe UI Symbol, DejaVu Sans, or a Noto Math face, if the glyph does not render.

Troubleshooting the cube root symbol

It shows as a box □ or a question mark. That means the current font has no glyph at U+221B. The cube root sits in the Mathematical Operators block, which display and decorative fonts often skip, so switch to Cambria Math, Segoe UI Symbol, DejaVu Sans, or Noto Sans Math.

You typed √ or ∜ by accident. The plain radical √ (U+221A) has no index digit, the cube root ∛ carries a small 3 in the crook, and the fourth root ∜ (U+221C) carries a 4. If your math needs a different index, pick the matching glyph rather than the wrong root.

The radical will not stretch over the number. The single ∛ character is only the sign, so it does not draw a bar across whatever follows. That is fine for ∛8, but for a cube root over a long expression use Word’s equation editor, which builds a proper radical with an overbar.

221B then Alt+X in Word did nothing. The app is not reading decimal Unicode input. Use Word’s 221B then Alt+X, Character Map, or paste from the button above.

What the cube root symbol is used for

∛ marks the number whose cube equals the value under the radical: ∛8 = 2, because 2 × 2 × 2 = 8. It appears in algebra when you solve x³ = k, and in geometry to get the edge length of a cube from its volume, where side = ∛V. Engineers and statisticians also reach for it in scaling work and in the geometric mean of three quantities.

Related symbols

The sign people mix up with this one is the square root. Here is how to type the square root symbol √, which is the same radical without the small 3.

The fourth root ∜ adds a 4 in the same spot. Roots often sit beside a plus-minus sign in solutions like x = ∛a ± b.

Frequently asked questions

How do I write a cube root over a whole expression?

The single ∛ glyph will not stretch over content, so use an equation editor. In Word, press Alt+= to start an equation, then use the Radical button and set the index to 3. Google Docs offers Insert → Equation, and LaTeX users write \sqrt[3]{x+2}.

Is ³√ the same as the cube root symbol ∛?

They look alike but are not the same. ³√ is two characters, a superscript 3 placed before a plain radical, faked to resemble a cube root.

∛ is one dedicated character (U+221B). The single character is cleaner to copy, sorts and searches correctly, and will not split at a line end, so prefer it when the app supports it.

Why does the cube root symbol look different in my browser than in Word?

Fonts. Each program draws U+221B with whatever font it is using, and the small 3 sits at slightly different sizes and positions across faces. As long as the code point is U+221B, it is the correct character even when the exact shape varies.

Can I type the cube root symbol without the numeric keypad on a laptop?

Yes. Several methods skip Alt codes entirely: Word’s 221B then Alt+X, the copy button on this page, Character Map, or a phone or Mac text shortcut. The 221B then Alt+X in Word method is the only one that needs the keypad, and it is also the least reliable, so it is the one to skip on a laptop.

Will the cube root symbol show up correctly on someone else’s phone?

Usually yes. ∛ is a standard text character, not an emoji, so it does not turn into a picture, and current iOS and Android system fonts include it. The risk is an old device or a stripped-down app font, so in a document, choose a common font so the reader sees the glyph rather than a box.

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