How to Type the Diameter Symbol
Ways to type Ø and related technical symbols for measurements, drawings, and specs.
Which diameter symbol should you use?
For many engineering notes, Ø is commonly used as a diameter sign. The dedicated diameter sign ⌀ also exists in Unicode, but it is not always supported by every font. If you are sharing documents widely, test the font before sending.
Copy-paste is often safest
Unlike copyright or degree symbols, diameter shortcuts vary by operating system and app. If you are writing a drawing note, spreadsheet, or product spec, copying Ø or ⌀ avoids layout surprises.
Use clear spacing
A readable format is Ø 25 mm or ⌀25 mm. Be consistent within the same document so readers do not wonder whether two styles mean different things.
Related symbol collections
If you want more options, browse our measurement symbols, math symbols. These pages are useful when you need to compare similar characters before copying one into a document.
Is Ø the same as zero?
No. Ø is a letter/symbol shape used in technical contexts; it should not be substituted with the number 0.