The TV stand's width is the most important criterion that decides the stability with which it will support the TV set. Hence, you should be choosing the size of your TV stand depending on how big your TV set is. Here is the guide:
TV size            TV stand width
Up to 32"                    28"
32 to 39"                     Between 30" and 45"
50" to 54"                   Between 46" and 49"
55" to 59"                   Between 50" and 53"
60" to 64"                   Between 54" and 57"
65" to 69"                   Between 58" and 62"
70" and above            63" or more