Usage and configuring i3 window manager in Ubuntu

i3 is a lightweight, keyboard-driven tiling window manager for X11 that automatically arranges your windows in non-overlapping tiles instead of free-floating, overlapping windows. On Ubuntu you install it in one command with sudo apt install i3 (it ships in the universe repository), then log out and pick i3 from the session gear on the login screen. On first launch it generates a config at ~/.config/i3/config, and from there you control everything from the keyboard using a modifier key (Mod, usually the Super/Windows key).

What is i3 and why use it?

i3 (i3wm) is a tiling window manager: rather than dragging and resizing overlapping windows with the mouse, i3 splits the screen into tiles and lets you navigate, resize, and rearrange windows entirely from the keyboard. It is small, fast, well documented, and actively maintained (i3 v4.x in 2026), which makes it popular for developers, servers with a lightweight GUI, and anyone who wants a distraction-free, mouse-light workflow.

Key ideas:

• Tiling — new windows automatically fill available space; no manual placement.
• Keyboard-first — launch apps, move focus, and switch workspaces with Mod key combinations.
• Workspaces — numbered virtual desktops you jump between instantly.
• Status bar — i3bar with i3status shows time, battery, network, and CPU.

Installing i3 on Ubuntu

i3 is packaged in Ubuntu's official universe repository, so you do not need any third-party APT repository. Install it directly:

# Make sure the universe repo is enabled (it is by default on Ubuntu Desktop)
sudo add-apt-repository universe
sudo apt update

# Install i3 (pulls in i3-wm, i3status, i3bar and dmenu)
sudo apt install i3

That is the recommended way to install i3 today. Older guides told you to add the third-party debian.sur5r.net repository — that is no longer necessary on Ubuntu, and using the distribution package keeps i3 updated through normal system upgrades.

A note on "i3-gaps": i3-gaps used to be a separate fork that added configurable gaps between windows. It was merged into mainline i3 in 2021, so there is no longer a separate i3-gaps package — the gaps feature now ships in the standard i3 package. If a tutorial tells you to install i3-gaps, you can ignore it and just install i3.

After installing, log out of your current session. On the login screen click the gear (session) icon and select i3, then log in. The first time i3 starts it asks whether to generate a config file — press Enter to create ~/.config/i3/config, and choose your modifier key when prompted (the Super/Windows key is the common choice).

i3 on Wayland: use Sway

Modern Ubuntu defaults to a Wayland session, while i3 is an X11 window manager. i3 still works perfectly under the X11 (Xorg) session, which Ubuntu continues to ship, so you can simply choose i3 from the login screen as described above.

If you specifically want a Wayland setup, use Sway, the drop-in Wayland-compatible successor to i3. Sway reads an i3-style configuration, so your keybindings and layout carry over almost unchanged:

# Sway: an i3-compatible tiling compositor for Wayland
sudo apt install sway

# Sway reads ~/.config/sway/config (same syntax as i3)
# Copy the default to start customising:
mkdir -p ~/.config/sway
cp /etc/sway/config ~/.config/sway/config

Essential keybindings

Throughout the i3 docs, Mod refers to your chosen modifier key (Mod1 is Alt, Mod4 is Super/Windows). These are the defaults you will use constantly:

• Mod + Enter — open a terminal
• Mod + d — open the application launcher (dmenu)
• Mod + Shift + q — close the focused window
• Mod + j / k / l / ; — move focus left/down/up/right
• Mod + Shift + j / k / l / ; — move the focused window
• Mod + f — toggle fullscreen for the focused window
• Mod + v — split the next window vertically; Mod + h — split horizontally
• Mod + Shift + Space — toggle floating mode for a window
• Mod + r — resize mode (then use the arrow keys)
• Mod + Shift + c — reload the config; Mod + Shift + r — restart i3 in place
• Mod + Shift + e — exit i3 (with a confirmation prompt)

Working with workspaces

Workspaces are numbered virtual desktops. You switch to a workspace, and any windows you open live there until you move them:

• Mod + 1 ... 0 — switch to workspace 1 through 10
• Mod + Shift + 1 ... 0 — move the focused window to that workspace

A common pattern is to dedicate workspaces by task — for example workspace 1 for your editor, 2 for the browser, 3 for terminals — so you can jump between contexts with a single keystroke.

Configuring i3

All configuration lives in a single plain-text file at ~/.config/i3/config. Edit it, then reload with Mod + Shift + c. A few useful snippets:

# Set the modifier key to Super/Windows
set $mod Mod4

# Open a terminal with Mod+Enter
bindsym $mod+Return exec i3-sensible-terminal

# Application launcher
bindsym $mod+d exec --no-startup-id dmenu_run

# Add a 10px gap between tiled windows (gaps are built into mainline i3)
gaps inner 10

# Auto-assign apps to workspaces
assign [class="Firefox"] $ws2

# Run programs at startup
exec --no-startup-id nm-applet

The status bar (i3bar and i3status)

i3 shows a status bar at the bottom of the screen via i3bar, and the content (clock, battery, network, disk, CPU load) is produced by i3status. The bar { ... } block in your i3 config controls it:

bar {
    status_command i3status
    position bottom
}

To customise what the bar displays, copy the default i3status config and edit it:

mkdir -p ~/.config/i3status
cp /etc/i3status.conf ~/.config/i3status/config

# Then edit ~/.config/i3status/config to add/remove modules
# (battery, wireless, ethernet, disk, load, tztime, etc.)

Running i3 on a minimal/server install

If you want a lean desktop — for example, a development box or a server with an occasional GUI — start from Ubuntu Server (or a minimal install), then add only X and i3. This avoids pulling in a full GNOME desktop and its applications, which would otherwise be unnecessary weight for an i3-only setup:

# Install a minimal X server and i3
sudo apt update
sudo apt install --no-install-recommends xorg i3

# Start i3 manually from a TTY (no display manager needed)
startx /usr/bin/i3

Because there is no other desktop environment installed, startx launches straight into i3. This kind of lean, reproducible Linux setup is exactly what we do day to day at MicroPyramid — with 12+ years of DevOps and Linux server experience across 50+ projects for startups and enterprises, we provision, harden, and maintain Ubuntu servers and developer workstations so teams can focus on shipping rather than fighting their tooling.

Frequently asked questions

Is i3 still maintained in 2026?

Yes. i3 is actively maintained and on the v4.x series in 2026. It ships in Ubuntu's official universe repository, so you can install and update it with standard apt commands — there is no need for the old third-party debian.sur5r.net repository that older tutorials reference.

Do I still need a separate i3-gaps package?

No. i3-gaps was a fork that added window gaps, and it was merged into mainline i3 in 2021. The gaps feature is now part of the standard i3 package, so you only install i3 and use directives like gaps inner 10 directly in your config.

Does i3 work on Wayland?

i3 itself is an X11 window manager and runs under Ubuntu's X11 (Xorg) session. If you need a native Wayland setup, use Sway, the i3-compatible Wayland compositor — it reads an i3-style config, so most of your keybindings and layout settings transfer with little or no change.

Where is the i3 configuration file?

i3 stores its configuration in a single plain-text file at ~/.config/i3/config (older installs may use ~/.i3/config). Edit that file and reload it live with Mod + Shift + c, or restart i3 in place with Mod + Shift + r.

How do I switch back to GNOME after trying i3?

Nothing is removed when you install i3 — it is added as an extra session. Log out, click the session gear icon on the login screen, choose Ubuntu (GNOME) instead of i3, and log back in.