Turn off the monitor and place it on a flat surface
Measure the visible screen area diagonally from one corner to the opposite corner
Do not include the bezel or frame in the diagonal measurement
Use a tape measure or ruler for accuracy
Record the diagonal length in inches or centimeters
Measure the width from left edge of the screen to right edge of the screen if needed
Measure the height from top edge of the screen to bottom edge of the screen if needed
Measure the full monitor size separately if you need the outer dimensions
Check the stand height and base width if you need desk space measurements
Verify the aspect ratio if comparing screen shapes or sizes