I have used both round and rectangular. For the round, I fold yard goods in half (depending on size of table topper you want), length-wise, then width-wise (you'll have two folds); then tie a pencil to a piece of string, the length of which is the radius of the topper + margins. Put the end of the string at the corner of the two folds, then draw a line with the pencil on the string extended the length you'll need (the radius of the circle). Cut on that line and you'll have a complete circle. You can PM me if questions.