How big of a television can I put on top?

Any Size. There is no limit to the size of the television that you place above the mantel. Keep in mind that TVs are measured diagonally. A 55″ – 60″ inch television looks perfect above your mantel. Of course, you can put something a little bit larger and it will be slightly wider than the mantel, but that’s really not a problem. Smaller is also not a problem. Put whatever size TV above your fireplace that seems like a good fit for your living room and lifestyle.