WP Dev Powers – Display Screen Dimensions To Admin Plugin - Rating, Reviews, Demo & Download
Plugin Description
This plugin displays the current screen dimensions to admin users only.
While this plugin is activated, admin users will see a bar at the bottom of your websites front end that displays the current width & height of your browser window. If you resize your window and refresh the page, the displayed dimensions will update. If you upgrade to the Pro Version, the displayed dimensions will update live as you resize the page.