How to Resize Tmux Panes

tmux is one of the best terminal multiplexers out there. I’ve been using tmux for 5+ years and I can’t think any development workflow without it.

Being able to have multiple sessions/windows/panes in a single terminal instance has definitely great benefits. It also has persistent sessions and sharing capabilities as well.

By default when creating panes — whether horizontal or vertical, tmux splits the window into 50% panes. But sometimes I just need a small pane to look at.

# horizontally
:split-window -h
# vertically
:split-window -v

In order to resize tmux panes, you first hit your tmux prefix (ctrl + b is the default one. Mine is ctrl + a.), and then the colon key :. This brings up a tmux command mode prompt at the bottom of your screen.

For resizing panes general args syntax is like below:

:resize-pane -$DIRECTION $cell-size

Below is an example of the entire resize pane command that resizes the active pane to the down by 30 cells. Cell is the unit in which tmux resizes:

:resize-pane -D 30

Here are examples for all directions:

:resize-pane -L 20 # Resizes the current pane Left by 20 cells
:resize-pane -R 20 # Resizes the current pane Right by 20 cells
:resize-pane -D 20 # Resizes the current pane Down by 20 cells
:resize-pane -U 20 # Resizes the current pane Upward by 20 cells

$ tmux resize-pane -D 10

All done!