Arrange windows

kitty has the ability to define its own windows that can be tiled next to each other in arbitrary arrangements, based on Layouts, see below for examples:

Screenshot, showing vim, tig and git running in kitty with the Tall layout

Screenshot, showing windows with arbitrary arrangement in the Splits layout

There are many different layouts available. They are all enabled by default, you can switch layouts using next_layout (ctrl+shift+l by default). To control which layouts are available use enabled_layouts, the first listed layout becomes the default. Individual layouts and how to use them are described below.

The Stack Layout

This is the simplest layout. It displays a single window using all available space, other windows are hidden behind it. This layout has no options:

enabled_layouts stack

The Tall Layout

Displays one (or optionally more) full-height windows on the left half of the screen. Remaining windows are tiled vertically on the right half of the screen. There are options to control how the screen is split horizontally bias (an integer between 10 and 90) and options to control how many full-height windows there are full_size (a positive integer). The mirrored option when set to true will cause the full-height windows to be on the right side of the screen instead of the left. The syntax for the options is:

enabled_layouts tall:bias=50;full_size=1;mirrored=false

┌──────────────┬───────────────┐
│              │               │
│              │               │
│              │               │
│              ├───────────────┤
│              │               │
│              │               │
│              │               │
│              ├───────────────┤
│              │               │
│              │               │
│              │               │
└──────────────┴───────────────┘

In addition, you can map keys to increase or decrease the number of full-height windows, or toggle the mirrored setting, for example:

map ctrl+[ layout_action decrease_num_full_size_windows
map ctrl+] layout_action increase_num_full_size_windows
map ctrl+/ layout_action mirror toggle
map ctrl+y layout_action mirror true
map ctrl+n layout_action mirror false

You can also map a key to change the bias by providing a list of percentages and it will rotate through the list as you press the key. If you only provide one number it’ll toggle between that percentage and 50, for example:

map ctrl+. layout_action bias 50 62 70
map ctrl+, layout_action bias 62

The Fat Layout

Displays one (or optionally more) full-width windows on the top half of the screen. Remaining windows are tiled horizontally on the bottom half of the screen. There are options to control how the screen is split vertically bias (an integer between 10 and 90) and options to control how many full-width windows there are full_size (a positive integer). The mirrored option when set to true will cause the full-width windows to be on the bottom of the screen instead of the top. The syntax for the options is:

enabled_layouts fat:bias=50;full_size=1;mirrored=false

┌──────────────────────────────┐
│                              │
│                              │
│                              │
│                              │
├─────────┬──────────┬─────────┤
│         │          │         │
│         │          │         │
│         │          │         │
│         │          │         │
│         │          │         │
└─────────┴──────────┴─────────┘

This layout also supports the same layout actions as the Tall layout, shown above.

The Grid Layout

Display windows in a balanced grid with all windows the same size except the last column if there are not enough windows to fill the grid. This layout has no options:

enabled_layouts grid

┌─────────┬──────────┬─────────┐
│         │          │         │
│         │          │         │
│         │          │         │
│         │          │         │
├─────────┼──────────┼─────────┤
│         │          │         │
│         │          │         │
│         │          │         │
│         │          │         │
└─────────┴──────────┴─────────┘

The Splits Layout

This is the most flexible layout. You can create any arrangement of windows by splitting existing windows repeatedly. To best use this layout you should define a few extra key bindings in kitty.conf:

# Create a new window splitting the space used by the existing one so that
# the two windows are placed one above the other
map f5 launch --location=hsplit

# Create a new window splitting the space used by the existing one so that
# the two windows are placed side by side
map f6 launch --location=vsplit

# Create a new window splitting the space used by the existing one so that
# the two windows are placed side by side if the existing window is wide or
# one above the other if the existing window is tall.
map f4 launch --location=split

# Rotate the current split, changing its split axis from vertical to
# horizontal or vice versa
map f7 layout_action rotate

# Move the active window in the indicated direction
map shift+up move_window up
map shift+left move_window left
map shift+right move_window right
map shift+down move_window down

# Move the active window to the indicated screen edge
map ctrl+shift+up layout_action move_to_screen_edge top
map ctrl+shift+left layout_action move_to_screen_edge left
map ctrl+shift+right layout_action move_to_screen_edge right
map ctrl+shift+down layout_action move_to_screen_edge bottom

# Switch focus to the neighboring window in the indicated direction
map ctrl+left neighboring_window left
map ctrl+right neighboring_window right
map ctrl+up neighboring_window up
map ctrl+down neighboring_window down

# Set the bias of the split containing the currently focused window. The
# currently focused window will take up the specified percent of its parent
# window's size.
map ctrl+. layout_action bias 80

# Maximize the active window along the horizontal axis (fill full width),
# keeping other windows visible in their vertical positions. Press again to
# restore the original layout.
map ctrl+alt+right layout_action maximize horizontal

# Maximize the active window along the vertical axis (fill full height),
# keeping other windows visible in their horizontal positions. Press again
# to restore the original layout.
map ctrl+alt+up layout_action maximize vertical

# Equalize all splits so that windows share available space proportionally.
map ctrl+shift+e layout_action equalize

Windows can be resized using Resizing windows. You can swap the windows in a split using the rotate action with an argument of 180 and rotate and swap with an argument of 270. The maximize action expands the active window to fill the maximum available space along a single axis while keeping the rest of the layout intact. Use maximize horizontal to fill the full width and maximize vertical to fill the full height. Calling it again restores the original split sizes. The equalize action redistributes space so that all windows along each split axis receive an equal share.

This layout takes three options. equalize_on_window_close automatically equalizes split sizes whenever a window is closed, keeping remaining windows balanced without needing an explicit keybinding:

enabled_layouts splits:equalize_on_window_close=true

proportional preserves the relative sizes of siblings along the same split axis when adding, removing or repositioning windows. A new window receives the same weight as the window being split, and the siblings are scaled to fit. For example, splitting either of two equally sized side-by-side windows makes three equally sized windows. Manually adjusted proportions are preserved when windows are closed. Splits along the other axis keep their relative sizes:

enabled_layouts splits:proportional=true

This option is disabled by default. An explicit launch --bias overrides proportional sizing for that new window. If equalize_on_window_close is also enabled, closing a window equalizes the layout instead of preserving its weights. The option is saved as part of a session.

Dragging a divider resizes only the two adjacent regions along its axis. Other dividers in the same row or column stay in place, including after repositioning windows. Nested dividers follow the mouse in character-cell steps relative to their own region, and stop when an adjacent region reaches its minimum size.

split_axis controls whether new windows are placed into vertical or horizontal splits when a --location is not specified. A value of horizontal (same as --location=vsplit) means when a new split is created the two windows will be placed side by side and a value of vertical (same as --location=hsplit) means the two windows will be placed one on top of the other. A value of auto means the axis of the split is chosen automatically (same as --location=split). By default:

enabled_layouts splits:split_axis=horizontal

┌──────────────┬───────────────┐
│              │               │
│              │               │
│              │               │
│              ├───────┬───────┤
│              │       │       │
│              │       │       │
│              │       │       │
│              ├───────┴───────┤
│              │               │
│              │               │
│              │               │
└──────────────┴───────────────┘

Added in version 0.17.0: The Splits layout

The Horizontal Layout

All windows are shown side by side. This layout has no options:

enabled_layouts horizontal

┌─────────┬──────────┬─────────┐
│         │          │         │
│         │          │         │
│         │          │         │
│         │          │         │
│         │          │         │
│         │          │         │
│         │          │         │
│         │          │         │
│         │          │         │
└─────────┴──────────┴─────────┘

The Vertical Layout

All windows are shown one below the other. This layout has no options:

enabled_layouts vertical

┌──────────────────────────────┐
│                              │
│                              │
│                              │
├──────────────────────────────┤
│                              │
│                              │
│                              │
├──────────────────────────────┤
│                              │
│                              │
│                              │
└──────────────────────────────┘

Docked windows

Added in version 0.50.0.

A kitty window can be docked to an edge of another kitty window or to an edge of the tab. Docked windows are placed outside the layout, which arranges the other windows in the space that remains. They are useful for things like status bars, file trees or a shell kept next to an editor. Create them with the launch action, for example:

# A one line status bar at the bottom of the tab that never gets keyboard focus
map f1 launch --type=tab-dock --dock-edge=bottom --dock-size=1 --dock-skip-focus my-status-bar
# A file tree using a quarter of the width of the active window, at its left
map f2 launch --type=window-dock --dock-edge=left --dock-size=25% yazi

The size of a dock is a number of rows (for docks at the top or bottom edge) or columns (for docks at the left or right edge), or with a % suffix, a percentage of the window or tab being docked to. When there are several docks at an edge, later docks are placed inside earlier ones. When there is not enough space for all the docks, the docks created last are made smaller first.

A window-dock belongs to the window it is docked to. It is shown whenever that window is shown, moves with it when it is moved to another tab and is closed when it is closed. A tab-dock is closed when the last window in the tab that is not docked is closed.

Docks can be focused like other windows, by clicking on them, with neighboring_window or nth_window with a negative number, unless they were created with launch --dock-skip-focus. Docks are not part of the layout, so they are not affected by actions such as move_window, next_window or layout_action. Docks are saved in sessions.

Resizing windows

You can resize windows inside layouts. The easiest method is to simply drag the window borders using a mouse, controlled by the option window_drag_tolerance. Note that technically this resizes layout slots not actual windows, so it does not work exactly like resizing OS Windows on your desktop. Instead, the layout is changed and potentially multiple windows get resized when dragging a single border.

For keyboard friendly resizing, press ctrl+shift+r (also ⌘+r on macOS) to enter resizing mode and follow the on-screen instructions. In a given window layout only some operations may be possible for a particular window. For example, in the Tall layout you can make the first window wider/narrower, but not taller/shorter. Note that what you are resizing is actually not a window, but a row/column in the layout, all windows in that row/column will be resized.

By default, hold Alt with W, N, T, or S to take a fraction of the remaining resize steps in that direction. The default is one third, rounded up: five remaining steps become two, and one remaining step becomes one. Resizing stops at the layout’s size limit. Ordinary letters (including uppercase letters) keep their normal step size unless Shift is selected as the fractional modifier, and Ctrl doubles it. To choose a different fraction, pass --fraction to the resize kitten, for example:

map kitty_mod+r kitten resize_window --fraction=1/4
# macOS
map cmd+r kitten resize_window --fraction=1/3

Inside the resize page, 1 selects the Window strategy and 2 selects the Edge strategy. M switches the fractional modifier between Alt and Shift, and F opens fraction presets or a custom ratio/decimal. Each strategy’s modifier and fraction are saved independently, together with the selected strategy. Explicit --strategy and --fraction options override saved values for that invocation.

F opens fraction settings for the active strategy; C accepts a custom ratio or decimal. The other strategy’s saved settings are kept separately.

To move a specific divider in the Splits layout, select the edge strategy:

map kitty_mod+r kitten resize_window --strategy=edge --fraction=1/3
# macOS, with a different fractional step
map cmd+r kitten resize_window --strategy=edge --fraction=1/4

First press H, J, K, or L to select the left, bottom, top, or right edge of the current pane. Arrow keys also work. This first key only selects the edge. Outside edges have no internal divider and cannot be selected. If there is exactly one internal edge, it is selected automatically on entering this strategy. Then use H/L for a left or right edge, or J/K for a top or bottom edge, to move the selected divider in the direction of the key. Neighboring parallel dividers stay in place; perpendicular subtrees resize as units.

The chosen Alt/Shift modifier takes the configured fraction of the remaining steps; Ctrl doubles the normal step. The other modifier retains the normal step size. Esc returns to edge selection; press it again to exit. Enter or Q exits immediately.

In Splits, either strategy uses R to restore the divider proportions saved when resize mode opened, rather than equalizing the layout. If the split structure has changed since then, restoration is refused. The initial default --strategy=window retains the usual width/height controls. Other layouts, and Splits when resize mode was opened in a different layout, keep Window’s default-size reset behavior. Starting the resize kitten again while its page is open replaces the page, applying the new options and keeping the saved sizes.

You can also define shortcuts in kitty.conf to make the active window wider, narrower, taller, or shorter by mapping to the resize_window action, for example:

map ctrl+left resize_window narrower
map ctrl+right resize_window wider
map ctrl+up resize_window taller
map ctrl+down resize_window shorter 3
# reset all windows in the tab to default sizes
map ctrl+home resize_window reset

The resize_window action has a second optional argument to control the resizing increment (a positive integer that defaults to 1).

Some layouts take options to control their behavior. For example, the Fat and Tall layouts accept the bias and full_size options to control how the available space is split up. To specify the option, in kitty.conf use:

enabled_layouts tall:bias=70;full_size=2

This will have 2 instead of a single tall window, that occupy 70% instead of 50% of available width. bias can be any number between 10 and 90.

Writing a new layout only requires about two hundred lines of code, so if there is some layout you want, take a look at one of the existing layouts in the layout package and submit a pull request!