How to split a pane in tmux
Side-by-side split, or stacked split:
keysprefix + % (left/right) · " (top/bottom)
Why the default keys feel backwards
tmux calls split-window -h a "horizontal split" because the dividing line runs top-to-bottom — but your panes end up side by side, which most people call a vertical split. Don't fight it: think in results. % looks like two things side by side; " looks like two marks stacked.
Rebind to | and - (what almost everyone does)
The most popular rebind in any .tmux.conf — the symbols look like the split they create, and adding -c '#{pane_current_path}' makes new panes open in your current directory instead of your home directory:
bind | split-window -h -c "#{pane_current_path}"
bind - split-window -v -c "#{pane_current_path}"Control the size at split time
-l takes a size in cells or a percentage: split-window -h -l 30% gives the new pane 30% of the width. -b puts the new pane before (left/above) the current one.
Related
Verified against tmux 3.6 · updated July 2026 · back to the full cheat sheet