When you are working with several application windows, switching between them and arranging them can shape how you use your desktop. i3 is an X11 tiling window manager that arranges windows as you open applications and provides configurable keyboard shortcuts.
I’ll show you how to install i3 on Ubuntu and select its session at login, then complete the first-run configuration.
TL;DR
Install i3 from Ubuntu’s package repository, then finish the first-run setup after selecting the i3 login session.
sudo apt update && sudo apt install i3
- Choose i3 from the login session menu.
- Complete the first-run wizard and select a modifier key.
What is i3 window manager?
i3 is an X11 tiling window manager. Its layout changes as you open applications, and configurable keybindings let you move focus between windows or use workspaces.
A desktop environment such as GNOME includes a broader set of desktop tools. A window manager handles window placement and interaction, so choosing i3 changes that part of the desktop session rather than replacing every Ubuntu application.
| Term | What it does here |
|---|---|
| i3 | Places and controls application windows in an X11 session. |
| Ubuntu desktop environment | Provides the broader desktop session and its applications. |
| $mod | The modifier key used in i3 keybindings, Alt by default in the official guide. |
Alt is i3’s documented default modifier, and the first-run wizard can create a configuration and let you choose another key such as the Windows key.
If you are comparing Ubuntu desktop options rather than window managers, see our overview of Ubuntu and Lubuntu. Our separate explanation of desktop environments and window managers covers how those layers differ. For a wider set of choices, see our Linux desktop environment roundup.
What you need before installing i3 on Ubuntu
Use an Ubuntu desktop session with administrator access to install packages. Before changing anything, check which Ubuntu release this machine runs:
. /etc/os-release && printf '%s\n' "$PRETTY_NAME"
Ubuntu 24.04.5 LTS
This command reads the release name from /etc/os-release. Your output reflects the Ubuntu release installed on your machine. You can compare it with our guide to checking the Ubuntu version if you need another method.
Keep the existing desktop session available while you try i3. The login screen’s session menu determines which window manager starts, and its appearance depends on the display manager installed on the machine.
How to install and start i3 on Ubuntu
Install the Ubuntu package, select its session at login, and finish the one-time configuration before opening applications.
Step 1: Install the Ubuntu i3 package
Refresh the package index and install i3 with apt:
sudo apt update && sudo apt install i3
Ubuntu’s package archive lists i3-wm as an Ubuntu package and describes its purpose as an improved dynamic tiling window manager. The i3 package is the distribution’s user-facing installation choice and includes related i3 components.
Use Ubuntu’s repository for the standard installation. The i3 project documents a separate repository for people who specifically need its latest stable release, but adding a third-party apt source changes the machine’s package trust and update path.
If you want to confirm which packages apt sees as installed, follow our guide to listing installed Ubuntu packages.
Step 2: Choose i3 from the login session menu
When installation finishes, sign out of the current desktop. At the login screen, open the session chooser, select i3, and sign in again. The chooser’s location and icon vary with the display manager, so use its session menu rather than assuming every Ubuntu login screen has the same gear button.
Selecting a different session at login does not uninstall GNOME. If you need the graphical desktop again, sign out and choose its session from the same menu.
Step 3: Create the initial i3 configuration
On first start, i3-config-wizard offers to create a configuration file and select the modifier key. Follow the prompts and note which key you choose. The official guide calls that key $mod and uses Alt by default in its documented default bindings.
The official guide documents two configuration paths, ~/.i3/config and ~/.config/i3/config. It also notes that an existing ~/.i3/config makes i3-config-wizard exit.
| Item | What to know |
|---|---|
| Config locations | ~/.i3/config or ~/.config/i3/config |
| Wizard behavior | It exits if ~/.i3/config already exists. |
| Key symbols | The wizard uses the current keyboard layout. |
Check the generated config before copying a binding written for another keyboard layout.
The configuration stores your keybindings and window behavior. The i3 guide explains how to edit it and reload the configuration, so check the guide before copying settings written for a different i3 version or fork.
For editing a plain-text configuration from a terminal, see our overview of terminal-based text editors.
Step 4: Open a terminal and arrange windows
Use the bindings documented by the i3 project to open a terminal and try the tiling behavior:
| Action | Default binding |
|---|---|
| Open a terminal | $mod+Enter |
| Open the application launcher | $mod+d |
| Enter fullscreen | $mod+f |
| Split the next window vertically | $mod+v |
| Split the next window horizontally | $mod+h |
In the official guide, pressing $mod+Enter opens a terminal, and opening another window gives i3 another window to place in the layout. The exact result depends on the current container layout and orientation, which you can change with i3’s documented commands.
Workspaces separate groups of windows. Use the configured workspace keybindings to move between them, and consult the official guide for the binding syntax in your configuration.
Check the session and key bindings
Use this checklist when the session or a shortcut behaves differently from the guide:
- If i3 is missing from the login menu, sign out fully and check the session chooser again. Its location depends on the display manager.
- If i3 remains missing, verify the Ubuntu package is installed and consult the display manager documentation before editing session files.
- If a shortcut differs, check the modifier selected in i3-config-wizard and inspect the active configuration.
- Ubuntu may package a different i3 version from upstream stable. Check Ubuntu’s package details before adding the project’s separate repository.
Conclusion
Ubuntu’s i3 package gets the session installed, while the login chooser and first-run wizard complete the move into i3. Keep the existing session available until you are comfortable with the new bindings.
If you decide to remove i3 later, use our instructions for uninstalling Ubuntu packages and review apt’s proposed changes before confirming.
Continue with the official i3 User’s Guide for its default keybindings and configuration details.
What is i3 window manager?
i3 is a tiling window manager for X11. It arranges application windows and provides configurable keyboard controls and workspaces.
How do I install i3 on Ubuntu?
Run sudo apt update && sudo apt install i3, then choose the i3 session at the login screen and complete the first-run configuration wizard.
Which key does i3 use as its modifier by default?
The i3 User’s Guide documents Alt, or Mod1, as the default $mod key. The first-run configuration wizard lets you choose a different modifier.
Does installing i3 remove GNOME from Ubuntu?
Installing i3 does not by itself uninstall GNOME. Sign out and choose the i3 session to use it, or select the GNOME session at login to return to that desktop.