52: How do I change Emacs's idea of the tab character's length? Set the variable default-tab-width. For example, to set tab stops every 10 characters, insert the following in your .emacs file: (setq default-tab-width 10) Do not confuse variable tab-width with variable tab-stop-list. The former is used for the display of literal tab characters. The latter controls what characters are inserted when you press the TAB character in certain modes.