How to Type O With a Slash Through It (Ø ø) on Any Keyboard

The letter O with a slash through it — written as Ø or ø — is a distinct letter in the Danish, Norwegian, and Faroese alphabets. It also appears in the International Phonetic Alphabet, mathematics, and engineering notation. Whether you need it for Scandinavian language writing, phonetic transcription, set theory, or technical documentation, this guide covers every way to type Ø and ø on any device and platform.

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What Is the O With a Slash?

The slashed O Ø ø is not simply a letter O with a decoration — it is an entirely separate letter in several languages with its own name, sound, and place in the alphabet. In Danish and Norwegian it is the last letter of the alphabet, sitting after Z. In Faroese it appears in the same position.

Beyond language, the symbol appears in several other contexts with completely different meanings:

Context	Symbol	Meaning
Danish / Norwegian / Faroese	Ø / ø	A distinct vowel letter (sounds like “uh” or “er”)
Swedish	Ö / ö	Equivalent sound, different character
German	Ö / ö	Umlaut — related but distinct character
Mathematics / Set Theory	∅	Empty set — a completely different symbol
Engineering / Technical	Ø	Diameter symbol
International Phonetic Alphabet	ø	Close-mid front rounded vowel
Music	ø	Half-diminished chord symbol

Critical distinction: The letter Ø (U+00D8) used in Danish and Norwegian is completely different from the empty set symbol ∅ (U+2205) used in mathematics, despite looking similar. They have different Unicode code points, different meanings, and are not interchangeable. This guide covers the letter Ø — see the section on related symbols for the empty set.

The full Unicode details for the letter:

Symbol	Name	Unicode
Ø	Latin capital letter O with stroke	U+00D8
ø	Latin small letter o with stroke	U+00F8

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How to Type O With Slash on Windows

Method 1: Alt Code (Fastest on Windows)

Make sure Num Lock is on, hold Alt, type the code on the numeric keypad, then release Alt:

• Alt + 0248 → ø (lowercase)
• Alt + 0216 → Ø (uppercase)

These are among the more commonly needed Alt codes for Scandinavian language writing and are worth memorizing if you type Danish or Norwegian regularly.

Some sources list Alt + 155 for ø and Alt + 157 for Ø using the older OEM code page. The four-digit versions with leading zeros (0248 and 0216) are more universally reliable across all Windows applications.

Method 2: Unicode Input (Microsoft Word)

1. Type the Unicode code point:
   • 00F8 for ø
   • 00D8 for Ø
2. Immediately press Alt + X
3. Word converts it instantly to the slashed O

Method 3: Copy and Paste

Copy directly from this page and paste anywhere: ø Ø

Works in every browser, app, text field, and document editor with no setup required.

Method 4: Character Map

1. Open Start and search “Character Map”
2. Search for “o with stroke” or “slashed o”
3. Select ø or Ø
4. Click Select, then Copy
5. Paste into your document

Method 5: Windows Emoji Panel

1. Press Windows key + . (period)
2. Go to the Symbols tab
3. Search for “o stroke” or “o slash”
4. Click to insert if the character appears in results

Method 6: Add a Scandinavian Keyboard Layout

For regular Danish or Norwegian writing, adding the appropriate keyboard layout is the most natural long-term solution:

1. Go to Settings > Time & Language > Language & Region
2. Click Add a language
3. Choose Danish, Norwegian Bokmål, or Norwegian Nynorsk
4. Switch layouts using Windows key + Space
5. On a Danish or Norwegian keyboard layout, ø has its own dedicated key — sitting to the right of the L key on the home row, in the same position as the semicolon on a US keyboard

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How to Type O With Slash on Mac

Method 1: Press and Hold (Easiest)

On macOS, press and hold the O key and a popup appears with accent and variant options. However, the standard press-and-hold popup on a US keyboard layout does not include ø by default — it shows ó ò ô ö õ ō but not ø.

To get ø through press and hold, you need to have a Danish or Norwegian keyboard added to your input sources.

Method 2: Option Key Shortcut (Best Mac Method)

Mac has a direct built-in shortcut for the slashed O:

Option + O → ø (lowercase) Option + Shift + O → Ø (uppercase)

This is one of the cleanest Option key shortcuts on Mac — a single keypress with no dead-key sequence required. It works in every app on macOS with no configuration needed.

Method 3: Character Viewer

1. Press Control + Command + Space
2. Search for “o with stroke” or “slashed o”
3. Double-click ø or Ø to insert

Method 4: Unicode Hex Input

1. Enable Unicode Hex Input under System Settings > Keyboard > Input Sources
2. Hold Option and type the Unicode code point:
   • 00F8 → ø
   • 00D8 → Ø

Method 5: Add a Scandinavian Keyboard on Mac

1. Go to System Settings > Keyboard > Input Sources
2. Click + and search for Danish or Norwegian
3. Add the keyboard
4. Switch using the input menu in the menu bar
5. On the Danish or Norwegian layout, ø has its own key to the right of L

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How to Type O With Slash on iPhone and iPad

Method 1: Press and Hold (Built-In — Easiest)

iOS supports accent popups natively — and unlike Mac, the iPhone keyboard does include ø in the press-and-hold popup for O:

1. Press and hold the O key
2. A popup row appears showing: ò ó ô õ ö ø ō
3. Slide to ø and release

For uppercase Ø:

1. Tap Shift to enable caps
2. Press and hold O
3. The popup shows Ø among the options
4. Slide to Ø and release

This is the standard method for iPhone users — no setup required.

Method 2: Add a Scandinavian Keyboard

For frequent Danish or Norwegian writing:

1. Go to Settings > General > Keyboard > Keyboards
2. Tap Add New Keyboard
3. Select Danish or Norwegian Bokmål
4. While typing, tap the globe icon to switch to the Scandinavian keyboard
5. The ø key appears to the right of the L key

Method 3: Text Replacement Shortcut

For even faster access without hunting through the popup:

1. Go to Settings > General > Keyboard > Text Replacement
2. Tap +
3. In Phrase, paste ø
4. In Shortcut, type something like oslash or oe
5. Tap Save

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How to Type O With Slash on Android

Method 1: Press and Hold (Built-In — Easiest)

Like iOS, most Android keyboards including Gboard support long-press popups for accented characters:

1. Press and hold the O key
2. A row of variants appears — look for ø in the popup
3. Slide to ø and release

Note: Not all Android keyboards include ø in the O press-and-hold popup. If it does not appear, use one of the methods below.

Method 2: Add Danish or Norwegian to Gboard

1. Open Gboard
2. Tap the globe icon or go to Gboard Settings > Languages
3. Tap Add Keyboard
4. Select Danish or Norwegian
5. Tap Done
6. Switch to the Scandinavian keyboard using the globe icon while typing
7. The ø key will appear on the keyboard as a dedicated character

Method 3: Personal Dictionary Shortcut

For a quick shortcut without switching keyboards:

1. Go to Gboard Settings > Dictionary > Personal Dictionary
2. Select your language
3. Tap +
4. Add ø as the word and oslash as the shortcut
5. Tap the checkmark to save

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How to Type O With Slash in Microsoft Word

Method 1: Alt + X (Fastest in Word)

Type 00F8 then press Alt + X — Word instantly converts it to ø. For uppercase: type 00D8 then Alt + X → Ø

Method 2: Built-In Word Shortcut

Word has a dedicated shortcut for the slashed O:

Ctrl + / then O → ø (lowercase) Ctrl + / then Shift + O → Ø (uppercase)

This is the cleanest method in Word. Press Ctrl + /, release both keys, then immediately press O. The two-step sequence produces the slashed O without needing to remember Unicode values.

Method 3: AutoCorrect Setup

Set Word to automatically replace a key sequence with ø:

1. Go to File > Options > Proofing > AutoCorrect Options
2. In Replace, type something like (oslash) or oe
3. In With, paste ø
4. Add a second rule: Replace (Oslash) With Ø
5. Click Add, then OK

Method 4: Insert > Symbol

1. Go to Insert > Symbol > More Symbols
2. Set Subset to Latin-1 Supplement
3. Find ø or Ø
4. Click Insert

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How to Type O With Slash in Google Docs

Method 1: Insert > Special Characters

1. Go to Insert > Special Characters
2. Search for “o with stroke” or “slashed o”
3. Click ø or Ø to insert

Method 2: Copy and Paste

Copy ø or Ø from this article and paste directly into your Google Doc — no additional steps needed.

Method 3: Substitutions

1. Go to Tools > Preferences > Substitutions
2. In Replace, type oe or (oslash)
3. In With, paste ø
4. Add a second rule for Ø
5. Click OK

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O With Slash in HTML and CSS

For web developers and publishers, here are all the correct ways to render the slashed O in code:

Lowercase ø

Method	Code	Result
HTML named entity	ø	ø
HTML numeric (hex)	ø	ø
HTML numeric (decimal)	ø	ø
CSS content property	content: "\00F8";	ø
Direct UTF-8	paste ø directly	ø

Uppercase Ø

Method	Code	Result
HTML named entity	Ø	Ø
HTML numeric (hex)	Ø	Ø
HTML numeric (decimal)	Ø	Ø
CSS content property	content: "\00D8";	Ø
Direct UTF-8	paste Ø directly	Ø

Best practice: ø and Ø are original HTML named entities with universal browser support dating back to HTML 2.0. Use them freely in markup. For CSS, use the Unicode escape. If your file is UTF-8 encoded (always include <meta charset="UTF-8"> in <head>), you can also paste ø and Ø directly into your HTML.

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Ø in Different Languages and Fields

Danish and Norwegian

In Danish and Norwegian, ø is a full independent letter — the last letter of the alphabet after Z. It represents a front rounded vowel sound, similar to the German ö or the French eu.

Common Danish and Norwegian words using ø:

• øl — beer
• ø — island
• grøn — green
• størrelse — size
• København — Copenhagen
• Bjørn — a common name (means “bear”)
• økonomi — economy

In both languages, ø and o are completely different letters — substituting one for the other produces either a misspelling or a different word entirely.

Faroese

Faroese, spoken in the Faroe Islands, uses ø in the same way as Danish and Norwegian. The Faroe Islands themselves take their name from Faroese Føroyar — which contains the ø.

Swedish

Swedish uses ö rather than ø for the equivalent sound. While ø and ö represent very similar vowel sounds across the Scandinavian languages, they are typographically distinct — ø has a diagonal stroke while ö has two dots (umlaut). Do not substitute one for the other in Swedish text.

International Phonetic Alphabet (IPA)

In the IPA, ø represents the close-mid front rounded vowel — the sound in French bleu (blue) or German schön (beautiful). Linguists, language teachers, and phonetics resources use it in transcriptions regardless of the language being described.

Engineering and Technical Drawing

The Ø symbol is widely used in engineering, architecture, and technical drawing to indicate diameter. When you see Ø12mm on a technical drawing, it means the diameter of the circle or hole is 12 millimeters. This usage is so common in technical fields that Ø is sometimes read aloud as “diameter” rather than “oh stroke.”

Mathematics

This is where the most important distinction lies. The empty set symbol ∅ (U+2205) looks very similar to Ø but is a completely different Unicode character used exclusively in mathematics and set theory to denote the set containing no elements. Using the letter Ø instead of ∅ in mathematical notation is technically incorrect, though the visual similarity means it is often accepted informally.

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Ø vs. ∅ vs. Ö vs. 0: Know the Difference

This symbol is frequently confused with several visually similar characters:

Symbol	Unicode	Name	Use
ø	U+00F8	Latin small letter o with stroke	Danish/Norwegian letter, IPA, diameter
Ø	U+00D8	Latin capital letter O with stroke	Uppercase version of above
∅	U+2205	Empty set	Mathematics — set with no elements
ö	U+00F6	Latin small letter o with diaeresis	Swedish, German, Finnish umlaut
Ö	U+00D6	Latin capital letter O with diaeresis	Uppercase umlaut
0	U+0030	Digit zero	The number zero
O	U+004F	Latin capital letter O	Regular letter O

Getting these right matters — particularly the ø vs. ∅ distinction in academic writing, and the ø vs. ö distinction when writing in Scandinavian versus German.

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Related Scandinavian and Nordic Characters

If you are writing in Danish, Norwegian, or another Nordic language, these related characters are worth having in your toolkit alongside ø:

Symbol	Name	Unicode	Mac Shortcut	Windows Alt Code	HTML Entity
ø	O with stroke (lower)	U+00F8	Option + O	Alt + 0248	ø
Ø	O with stroke (upper)	U+00D8	Option + Shift + O	Alt + 0216	Ø
æ	AE ligature (lower)	U+00E6	Option + ‘	Alt + 0230	æ
Æ	AE ligature (upper)	U+00C6	Option + Shift + ‘	Alt + 0198	Æ
å	A with ring (lower)	U+00E5	Option + A	Alt + 0229	å
Å	A with ring (upper)	U+00C5	Option + Shift + A	Alt + 0197	Å
ö	O with umlaut (lower)	U+00F6	Option + U then O	Alt + 0246	ö
Ö	O with umlaut (upper)	U+00D6	Option + U then Shift+O	Alt + 0214	Ö

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Quick Reference: O With Slash Cheat Sheet

	ø	Ø
Name	Latin small letter o with stroke	Latin capital letter O with stroke
Unicode	U+00F8	U+00D8
HTML entity	ø	Ø
HTML numeric	ø	Ø
Windows Alt code	Alt + 0248	Alt + 0216
Word shortcut	Ctrl + / then O	Ctrl + / then Shift+O
Word (Alt+X)	Type 00F8 + Alt+X	Type 00D8 + Alt+X
Mac shortcut	Option + O	Option + Shift + O
Mac (Viewer)	Ctrl+Cmd+Space, search “o stroke”	← same
iPhone / Android	Hold O, slide to ø	Hold Shift+O, slide to Ø
Scandinavian keyboard	Dedicated key (right of L)	Shift + dedicated key
CSS escape	\00F8	\00D8

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Final Thoughts

The O with a slash — ø and Ø — is one of those characters that looks exotic on a US keyboard but is completely straightforward once you know where to find it. Mac users have the easiest path with Option + O working instantly in every app. iPhone users can access it by pressing and holding O — it is right there in the popup without any setup. Windows users should commit Alt + 0248 to memory for ø, or use the Ctrl + / then O shortcut inside Word. For anyone writing regularly in Danish or Norwegian, adding the Scandinavian keyboard layout gives ø its own dedicated key — exactly where it belongs — and makes the whole experience feel natural. Developers building Nordic-language content should use ø — one of the original named HTML entities with support in every browser ever made.