The most common diameter symbol shortcut key on Windows is Alt + 0216: hold Alt, type 0216 on the number pad and release Alt to get Ø. Engineers, fitters and students use this letter for diameter because it is easy to type and looks right in most fonts.
The true technical diameter sign is a separate character. In Word, type 2300 and press Alt + X to get it. On a Mac, Option + Shift + O types Ø.
Quick facts
Ø on the number pad
Alt + 0216ø small
Alt + 0248True sign in Word
2300, then Alt + XAny app
Win + ., SymbolsExcel formula
=UNICHAR(8960)Mac
Option + Shift + O
Diameter symbol shortcut key methods
| Method | Keys | Symbol |
|---|---|---|
| Alt code, number pad | Alt + 0216 | Ø |
| Alt code, small | Alt + 0248 | ø |
| Unicode in Word | 2300, then Alt + X | ⌀ |
| Symbol panel | Win + ., Symbols tab | Ø or ⌀ |
| Excel formula | =UNICHAR(8960) | ⌀ |
| Mac | Option + Shift + O | Ø |
Ø is technically a Scandinavian letter, but it is accepted on most drawings and quotations. Use ⌀ where a standard or client asks for the exact technical sign. Whichever you choose, use the same one throughout a document so drawings, quotations and bills match.
Dia shortcut key on a laptop without a number pad
Alt codes need the separate number pad. On compact laptops, use the symbol panel (Win + .) or Word's Unicode method, 2300 then Alt + X. Some laptops hide a number pad on the J, K, L keys, switched on with Num Lock; small numbers printed on those keys show if yours has one. Once typed, keep the symbol in clipboard history with Win + V and pin it.
Diameter sign in Excel
For a heading or label, type Alt + 0216 into the cell. To show sizes such as 12 mm with a diameter sign while keeping the number usable in calculations, press Ctrl + 1, choose Custom and enter a format with the sign before 0. The symbols in Excel page explains custom formats.
In CAD and drawing programs
Technical drawing programs often have their own text code for the diameter sign that converts automatically inside a dimension or text note. Check the program's help for symbols in text; the code is usually two percent signs followed by a letter. When sending drawings to clients as PDF, confirm the symbol shows in the exported file, because some fonts replace it with a box.
When the diameter symbol does not appear
| Problem | Fix |
|---|---|
| Alt code types nothing | Use the number pad with Num Lock on |
| ⌀ shows as a box | Use a font such as Segoe UI Symbol, Cambria Math or Arial |
| Alt + X changes something else | Make sure 2300 is not attached to other letters or numbers |
| Mac types a different letter | Hold Option and Shift together with O |
More symbol keys
Other signs used in engineering and maths are on plus minus, euro and arrows, degree symbol and the full symbol shortcut keys page.
Frequently asked questions
What is the diameter symbol shortcut key?
How do I type the dia symbol in Word?
Type 2300 and press Alt + X for ⌀.
How do I type a diameter sign on a laptop?
Use Win + . and the symbols tab.
Is Ø the same as the diameter symbol?
They look alike; Ø is a letter widely used for diameter, ⌀ is the technical sign.
How do I add a diameter sign in Excel?
Type Alt + 0216 or use =UNICHAR(8960).