I am getting ready for two upcomng fall bazaars out west here. I made several sizes. When I looked it up prior to making my DIL one internet stated make 1/3 width of table by length plus 6 inch or so overhang each side. It would depend on if table leafs up or down. I did not make any square table toppers though as I didn't think many would use them. Tables vary so much. You could pass out your card for custom orders , not sure if I will do that as clock is ticking to holiday time already.