Television screen size is measured diagonally from corner to corner. For example, a 60-inch TV screen measures 60 inches from the lower-left corner of the screen to the upper-right corner.
To measure a TV screen, place one end of a tape measure on the bottom-left corner of the screen inside the bevel. Extend the tape measure diagonally to the top-right corner. This measurement is the screen size. The measurement should always be made inside the screen's bevel or frame, across the part where the picture is displayed. Always ensure that the TV is switched off before attempting to measure the screen.