[header] How to measure the size of a tv screen [title] Place the tape measure or measuring stick in the lower left hand corner of the tv's screen. [title] Be sure to start measuring where the actual screen begins, not from the plastic frame of the tv (known as the bevel). [title] Extend your tape measure or measuring stick to the upper right hand corner of the tv screen (diagonally from where you started). 
[title] Record the length between these two corners. [step] This is the screen's size.