First, use a sheet or blanket or something and audition the heights to see what looks best to you - that is the size to make! Second, if you want to make a bed skirt, remember that you only need to make the skirt part. Attach the skirt to a sheet that is just the size of the box spring. The maximum you should need would be about 20", so you get 2 pieces from a WOF. Roughly figuring 7" for each side and 6' for bottom = roughly 7 yards divided in half, you would only need 3 1/2 yards to make the whole bed skirt plus an old sheet to attach it to. That is a flat skirt, calculate how much more you need according to how full you want it gathered or pleated.
Last edited by klswift; 09-12-2018 at 07:13 AM.