How do I figure out what size my tv is?

I know you are supposed to measure from corner to corner diagonally. Is that just the glass or the plastic around it too?How do I figure out what size my tv is?
It's BEST to look at the model number, usually the first two numbers are the picture tube size.....





But when you measure only the picture tube it comes out smaller than the Model's size...that's because underneath the cabinet there is some more picture tube that you don't see....and that's used to mount the picture tube to the cabinet.





A 27 inch picture tube or model can be mistaken for a 25 inch TV set....the same applies with a 32 inch being mistaken for a 30 inch TV.....How do I figure out what size my tv is?
Just the glass.
People here are correct, its the glass width across the diagonal. The manufacturers cheat though and add about an inch or two. To be safe, round it up to one of the following figures...





14';, 17';, 19';, 21';, 24';, 26';, 27';, 30';, 32';, 36';, 37';, 40';, 42';





No manufacturer quotes a figure between these values. Weid I know.
On the Diagonal glass surface.





You'll find Plasmas and LCD tvs are more accurate than the old CRT ones. The CRT screens start further in behind the frame, so a 29'; TV would only measure about 27.5 - 28'; diagonally.





Bit of useless information, but some people didn't know that.
measure the glass on a diagonal
measure the glass, from corner to corner
If someone has a 32 inch television, the 32 inch is the measurement of the screen(glass) itself measured diagonally across the corners.