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U+2205 · Mathematical Operators

Empty Set ∅

The empty set symbol denotes the set that contains no elements. Mathematicians write A ∩ B = ∅ to say two sets share nothing, and it appears throughout set theory, probability and database theory. Informally, people also use it in notes and spreadsheets to mean "none" or "no result."

UnicodeU+2205
HTML∅
∅U+2205

Character codes

Unicode code pointU+2205
Decimal8709
HTML named entity∅
HTML (hex)∅
HTML (decimal)∅
CSS\2205
JavaScript\u2205
Python\u2205
UTF-8 bytesE2 88 85
UTF-162205
URL-encoded%E2%88%85

Character details

Official nameEMPTY SET
Unicode blockMathematical Operators
General categoryMath Symbol (Sm)
SymbolHero categoryMath Symbols
EmojiNo

How to type ∅

Windows

  • In Microsoft Word or Outlook: type 2205 then press Alt + X.
  • Open Character Map (search “Character Map” in Start), tick “Advanced view”, search for “empty set”, then Select and Copy.

Mac

  • Press Control + Command + Space to open the Character Viewer, search “empty set”, and double-click the result.
  • With the Unicode Hex Input keyboard enabled (System Settings → Keyboard → Input Sources), hold Option and type 2205.

iPhone & Android

  • Tap Copy at the top of this page, then long-press where you want it and choose Paste.

Docs & web

  • Google Docs: Insert → Special characters, then search “empty set” or enter U+2205.
  • HTML: ∅ or ∅
  • Excel / Google Sheets: =UNICHAR(8709)

Examples

  • A ∩ B = ∅
  • The solution set is ∅
  • {x ∈ ℝ : x² < 0} = ∅

Good to know

Don’t mix it up: It is often confused with Ø (U+00D8), a Danish and Norwegian letter, and with the diameter sign ⌀ (U+2300) used in engineering drawings.

Tip: The HTML named entity ∅ outputs this character.

Display: the character itself is always the same code point, but its shape comes from the font on the device showing it. If you see an empty box, the font lacks this glyph—the text is still correct.

Guides

Common Math Symbols and Their Meanings

Similar math symbols

Not Sign
Degree Symbol
Plus-Minus Sign
Multiplication Sign
Division Sign
Per Mille Sign
Prime (Feet / Minutes)
Double Prime (Inches / Seconds)
For All
Partial Differential
There Exists
Increment (Delta)
Element Of
N-Ary Product
Summation Sign
Minus Sign
Square Root Symbol
Infinity Symbol
Right Angle
Intersection
Union
Integral Sign
Therefore Sign

See all 714 math symbols →

Questions

What is the Unicode for ∅?

It is U+2205 (EMPTY SET), decimal 8709.

Is there a Windows Alt code for it?

No standard Alt code exists for this character. In Word type 2205 then Alt+X, or copy it from this page.

How do I type it on a Mac?

There is no built-in Option shortcut. Use the Character Viewer (Control + Command + Space) and search “empty set”, or copy it from this page.

What is the HTML code?

Use the named entity ∅ or the numeric reference ∅.