Diameter Symbol (⌀)

The diameter symbol ⌀ is Unicode U+2300, the engineering and drafting symbol indicating the diameter of a cylindrical or spherical feature. Press Copy to put it on your clipboard.

Unicode: U+2300
HTML: ⌀
Word: 2300 Alt+X

How to type the diameter symbol (⌀)

The quickest way is to press Copy above and paste. To type ⌀ yourself, use the method for your device below.

Windows

In Word or Outlook, type 2300 and press Alt + X. Alt + X converts the hex code before the cursor into the character, and back again.
Press Win + R, type charmap and press Enter. Tick “Advanced view”, search for Diameter Sign, then Select and Copy. Character Map is built into every version of Windows.

Mac

Press Control + Command + Space to open the Character Viewer, search for diameter and double-click it.
With the Unicode Hex Input keyboard enabled (System Settings → Keyboard → Input Sources), hold Option and type 2300.

Linux & ChromeOS

Press Ctrl + Shift + U, type 2300, then press Enter or Space. Works in GTK and IBus apps (GNOME, Firefox, Chrome, LibreOffice) and on ChromeOS.

iPhone & iPad

Copy ⌀ from this page, then go to Settings → General → Keyboard → Text Replacement and add it with a shortcut such as ;diam. The shortcut then turns into the symbol as you type, in every app.

Android

Copy ⌀ here, then open Gboard settings → Dictionary → Personal dictionary and add it with a shortcut.

Microsoft Word

Type 2300, then press Alt + X.
Insert → Symbol → More Symbols. Set “from” to Unicode (hex), type 2300 in “Character code” and click Insert.

Google Docs

Insert → Special characters, then search for “diameter” or draw it in the box.

Excel & Google Sheets

Enter =UNICHAR(8960) in a cell. It works in Excel 2013 and later and in Google Sheets.

HTML

Write ⌀ or ⌀ in your HTML.

What does ⌀ mean?

The ⌀ symbol, encoded in Unicode as DIAMETER SIGN (U+2300), is the official engineering, architectural, and geometric symbol used to denote diameter on technical drawings. Consisting of a circle crossed through its centre by a diagonal line sloping up and to the right at roughly 45 to 60 degrees, it precedes a dimension to indicate that the specified feature is circular, such as ⌀ 25 mm for a steel shaft or pipe fitting. Although typists often substitute the Scandinavian letter Ø or the mathematical empty set symbol ∅, only ⌀ has the correct circular geometry and centered slash. Explore related technical notations in technical symbols and our power symbol guide.

Common uses

Engineering blueprints: placed directly before numerical measurements (e.g., ⌀ 10.5) to designate circular hole or pin diameters
Plumbing and piping: specifying inside and outside diameters of conduits, tubing, and valves
Computer-aided design (CAD): typed into AutoCAD and SolidWorks dimension annotations using shorthand tags like %%c
Optics and photography: marking lens barrel thread diameters and filter sizes

Diameter Symbol codes for HTML, CSS and programming

Every code below produces ⌀. Use the HTML entity in web pages, the CSS escape in content, and the escape sequence in source code.

Codes for ⌀
Unicode code point	`U+2300`
HTML decimal	`⌀`
HTML hex	`⌀`
CSS content	`content: "\2300";`
JavaScript	`"\u2300"`
Python	`"\u2300"`
Python (by name)	`"\N{DIAMETER SIGN}"`
Java / C#	`"\u2300"`
UTF-8 bytes	`E2 8C 80`
UTF-16	`2300`
URL encoded	`%E2%8C%80`

⌀ vs look-alike characters

These characters look similar to ⌀ but have a different meaning and code. Pasting the wrong one can break search, sorting and screen readers.

Char	Name	When to use it
	Empty Set `U+2205`	Empty set symbol, a mathematical glyph that is typically narrower and italicised.
	Capital O with Stroke `U+00D8`	Latin capital letter O with stroke, a Scandinavian vowel that displays with letter proportions.
	Power Symbol `U+23FB`	Power symbol, which features a vertical line at the top rather than a full diagonal slash.

Symbols similar to ⌀

Click to copy, or open a symbol for its codes. See the full mac keyboard symbols collection.

⌀ character properties

Official Unicode name: DIAMETER SIGN
Also known as: diameter sign, engineering diameter symbol, slashed circle, pipe diameter, bore size symbol
Code point: U+2300
Unicode block: Miscellaneous Technical (U+2300–U+23FF)
General category: Other symbol (So)
Added in: Unicode 1.1 (1993)
Plane: Basic Multilingual Plane (0)
Emoji: No, it is a text symbol

Frequently asked questions

How do I type the diameter symbol in AutoCAD?

In AutoCAD text and dimension strings, type %%c. AutoCAD automatically converts that shorthand escape code into the proper diameter symbol ⌀ on drafting layouts.

Why shouldn't I use Ø or ∅ for diameter?

The letter Ø is a linguistic alphabet character in Danish and Norwegian, and ∅ is a mathematical set theory character. Using them in CAD or technical documentation causes inconsistent font rendering and breaks machine-readable drawing metadata.

Is there an alt code for the diameter symbol?

No. ⌀ is outside the Windows-1252 and code page 437 character sets, so no Alt + number code produces it. Copy it from this page, type 2300 then Alt + X in Word, or find it in Character Map.

How do I type the diameter symbol on a Mac?

There is no single Option shortcut for ⌀ on the US layout. Press Control + Command + Space to open the Character Viewer, search for “diameter” and double-click it, or copy it from this page.

What is the HTML code for the diameter symbol?

⌀ has no named HTML entity. Use the numeric reference ⌀ or ⌀, or paste the character directly into a UTF-8 page.

What is the Unicode for the diameter symbol?

⌀ is U+2300, officially named DIAMETER SIGN, in the Miscellaneous Technical block. It has been part of Unicode since version 1.1 (1993).