Free Ruler
Features: Horizontal and vertical rulers, in any color you like. Choose from pixel, millimeter, and inch units (press U to cycle). Float rulers above other applications (press F to toggle). Move windows independently or as a group (press G to toggle). Show or hide the shadow behind rulers (press S to toggle). Align rulers at mouse location (press O for origin). Reset ruler locations with Command-R.
Version 2.0.19 · Requires macOS 14.0