How to use the Compose key on Linux and Windows
The compose key is one of the most elegant methods for typing symbols and accented characters on computer keyboards. By tapping Compose followed by intuitive letter combinations—such as Compose + o + c for © or Compose + o + o for °—you can type hundreds of glyphs without memorizing numbers.
What is a Compose key and how does it work?
The compose key (sometimes abbreviated as Multi_key) is a dedicated keyboard function that converts intuitive two- or three-key sequences into special characters. Unlike Windows alt codes—which require holding down keys while typing arbitrary four-digit numbers on a number pad—the compose key uses sequential mnemonic keystrokes.
You tap the Compose key once and release it, then tap two or three logical letters in sequence. For example:
- Tap Compose, then o, then c → produces the copyright symbol © (a 'c' inside an 'o'). See our copyright symbol page.
- Tap Compose, then o, then o → produces the degree sign °. See our degree symbol page.
- Tap Compose, then t, then m → produces trademark ™.
- Tap Compose, then ', then e → produces é (e with acute accent).
- Tap Compose, then <, then 3 → produces a heart ♥.
The feature originated on DEC VT220 computer terminals in 1983 and has been standard on UNIX and Linux operating systems ever since.
1. How to enable the Compose key on Linux
Linux distributions include compose key functionality built right into the X11 and Wayland display servers. You only need to choose which physical key on your keyboard will act as the Compose key (popular choices include Right Alt, Caps Lock, or the Menu key):
- GNOME Desktop (Ubuntu, Fedora): Install GNOME Tweaks (
sudo apt install gnome-tweaks). Open Tweaks, go to Keyboard & Mouse, click Compose Key, and toggle it on. Select Right Alt or Caps Lock as your trigger key. - KDE Plasma: Open System Settings > Input Devices > Keyboard > Advanced. Expand “Position of Compose key”, check your preferred key (like Right Alt), and click Apply.
- X11 command line: To enable it instantly in any X11 terminal session, run:
setxkbmap -option compose:ralt.
2. Using WinCompose on Windows
Windows does not include a native compose key out of the box, but the open-source community created WinCompose, a lightweight background utility that brings the exact same Linux compose key functionality to Windows 10 and 11:
- Download and install the free, open-source WinCompose utility from GitHub.
- Launch WinCompose; a small icon appears in your system tray.
- Right-click the icon and choose Preferences to select your Compose key (Right Alt, Menu, or Scroll Lock).
- Start typing intuitive sequences in any Windows program!
WinCompose includes a searchable cheat sheet of over 2,000 preconfigured sequences and lets you define your own custom snippets. Learn more Windows shortcuts in our guide on how to type symbols on Windows.
3. Essential Compose key cheat sheet
Here are the most useful compose sequences categorized for daily writing:
| Symbol | Name | Key Sequence (after tapping Compose) |
|---|---|---|
| © | Copyright | o + c or O + C |
| ® | Registered Trademark | o + r or O + R |
| ™ | Trademark | t + m or T + M |
| ° | Degree Sign | o + o or 0 + ^ |
| ± | Plus-Minus | + + - |
| ≠ | Not Equal | / + = |
| ½ | One Half | 1 + 2 |
| ¼ | One Quarter | 1 + 4 |
| — | Em Dash | - + - + - |
| – | En Dash | - + - + . |
| « / » | Guillemets | < + < / > + > |
| € | Euro Sign | c + = or e + = |
| £ | British Pound | l + - or L + - |
| ¿ | Inverted Question | ? + ? |
| ¡ | Inverted Exclamation | ! + ! |
Browse mathematical notation like ± and ≠ in our math symbols collection.
4. Accents and diacritics via Compose key
Typing international accents with Compose follows natural grammatical intuition: tap Compose, tap the punctuation mark that looks like the accent, and tap the letter:
- Acute (á, é, í, ó, ú): Compose + ' + letter
- Grave (à, è, ì, ò, ù): Compose + ` + letter
- Umlaut / Diaeresis (ä, ë, ï, ö, ü): Compose + " + letter
- Circumflex (â, ê, î, ô, û): Compose + ^ + letter
- Tilde (ã, ñ, õ): Compose + ~ + letter
- Cedilla (ç, Ç): Compose + , + c
- Ring above (å, Å): Compose + o + a
- German Eszett (ß): Compose + s + s
Learn more system methods in our guide on how to type accents.
5. Creating custom sequences (.XCompose)
On Linux, you can define your own personal shortcuts by creating a file named ~/.XCompose in your home directory:
include "%L"
<Multi_key> <g> <m> : "Good morning! ☕"
<Multi_key> <s> <h> : "https://symbolhub.com"
Save the file and restart your desktop session. Tapping Compose followed by g and m immediately outputs your greeting. Learn how this compares with keyboard layouts in our guide to the US-International keyboard, or review Linux hex input in our guide on how to type Unicode on Linux.
Frequently asked questions
What is the Compose key on my keyboard?
Keyboards do not have a physical key labeled "Compose". On Linux and Windows, you assign an existing key (most commonly Right Alt, Caps Lock, or Menu) to act as Compose.
Do I hold down the Compose key while typing?
No. You tap and release Compose, then type the two sequence keys one after another. This is much easier on the fingers than holding chords.
How do I type a copyright symbol with Compose?
Tap Compose, then type o, then type c. The copyright symbol © appears instantly.
Can I use the Compose key on a Chromebook?
Yes. In ChromeOS Settings > Device > Keyboard, you can set the Search / Everything key or Right Alt as the Compose key.