Turn off the TV and measure the visible screen only, not the frame or bezel
Use a tape measure
Measure diagonally from one corner of the screen to the opposite corner
Start at the inside edge of the top-left corner and end at the inside edge of the bottom-right corner, or vice versa
Do not include the stand
Round to the nearest whole inch
Check the TV model specifications if you want the official listed screen size
Use the width and height measurements only if you need the exact panel dimensions