You can display the polygon count for the polygon objects in your scene using the Heads Up Display. The Heads Up Display indicates the number of polygon vertices, edges, faces, triangles, and UVs in the views without occluding your view of the objects.
Displaying the polygon count is particularly useful if your 3D scene is intended for use in an interactive video game. Interactive video games often have limitations on the number of polygons as a means to maintaining real-time interactivity.
To display the polygon count in the scene view
The Heads Up Display appears in the upper left corner of the view.
The left-hand column lists the total counts for all visible polygons, the middle column displays counts for selected polygons, and the right-hand column displays counts for selected components on objects that are partly visible in the view.