How to type the diameter symbol (Ø) on any device

The diameter symbol (Ø) is widely used in technical drawings, product descriptions and specifications to indicate the cross-section of round objects (e.g. Ø50mm). This symbol is also known as the slashed O and originally comes from the Scandinavian languages. Here you'll learn how to type this symbol on any device.

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Typing the diameter symbol on Windows

There are two handy methods to type the diameter symbol on Windows:

Method 1: Alt code (most common)

1. Make sure Num Lock is on
2. Hold down the Alt key
3. Type 0216 on the numeric keypad
4. Release the Alt key

The diameter symbol Ø now appears.

Note: For the lowercase ø, use Alt + 0248.

Method 2: Character Map

1. Open the Start menu and search for "Character Map"
2. Select the font you are using
3. Find the diameter symbol (Ø) in the table: it's among the Latin extended characters
4. Click "Select" and then "Copy"
5. Paste the character wherever you need it

Typing the diameter symbol on Mac

On a Mac, use the following key combination:

• Hold down Option (or Alt) + Shift
• Press the O key

This gives you the uppercase Ø. For the lowercase ø, hold down only Option and press O.

Typing the diameter symbol on Linux

On Linux you can type the diameter symbol via Unicode:

1. Press Ctrl + Shift + U
2. Type D8 (the Unicode code for Ø)
3. Press Enter or Space

For the lowercase ø, use F8 instead of D8.

Typing the diameter symbol on iPhone and iPad

On iOS you can type the diameter symbol as follows:

1. Open the keyboard
2. Press and hold the O key
3. A pop-up appears with variants, including Ø and ø
4. Slide your finger to the character you want and let go

Typing the diameter symbol on Android

On Android devices it works in a similar way:

1. Open the keyboard
2. Press and hold the O key
3. A menu appears with special versions of the O
4. Tap Ø to insert it

If you don't see the character, try a different keyboard, such as Google's Gboard.

Typing the diameter symbol in Word, Excel and PowerPoint

In Microsoft Office programs you have extra options:

Shortcut

• Type 00D8 and then press Alt + X (works in Word)

Via Insert Symbol

1. Go to Insert > Symbol > More Symbols
2. Under Font, select: "(normal text)"
3. Find the diameter symbol or type 00D8 in "Character code"
4. Click Insert

Setting up AutoCorrect

You can also create an AutoCorrect entry:

1. Go to File > Options > Proofing > AutoCorrect Options
2. Under "Replace", type something like diam
3. Under "With", type the character Ø
4. Click Add

Frequently asked questions (FAQ)

Is the diameter symbol the same as the Scandinavian letter Ø?

Yes, technically it's the same Unicode character (U+00D8). In Scandinavian languages (Danish, Norwegian) it's a vowel that sounds like the Dutch "eu". In technical contexts, the same symbol is used to indicate diameter.

When do I use Ø and when the word diameter?

In technical drawings and specifications, Ø is the standard notation (e.g. Ø50mm). In running text, it's better to write out "diameter" for readability. The symbol is especially useful in tables, drawings and short specifications.

Is there an alternative to the diameter symbol?

Some people use a slashed zero (∅) or even a regular zero with a line through it. However, the official diameter symbol according to ISO standards is Ø (U+00D8). The mathematical empty set symbol ∅ (U+2205) looks similar but has a different meaning.

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