How big a TV should I buy? | TV and Home Theater - CNET Reviews (click for full article) by Geoffrey Morrison July 11, 2012 9:47 AM PDT Updated: November 14, 2012 5:51 PM PST "37? 42? 50? 65? 90? There's an HDTV size for every room and every budget. But if you're not limited by a cabinet or entertainment center, how big of a TV can or should you get? The short answer: as big as you can afford. The longer answer depends on your room, your seating distance, your eyes, and the acceptance of any cohabitating co-deciders. There is a direct correlation between recommended screen size and seating distance. The farther away you sit, obviously, the smaller your TV appears. The ideal is to have a screen that fills a certain amount of your field of view, though how much is "ideal" is up for debate. THX recommends, for example, a viewing angle of 40 degrees, to create "an immersive cinematic experience." What does 40 degrees mean to those of us who love math in theory but not in practice? Skip the protractor, and multiply your seating distance (in inches or centimeters) by 0.84. This gets you the recommended screen diagonal."