So, because the fabric comes in 40-45 inch widths, you’ll need to decide how ruffly you want the skirt. If that’s big enough of a width for you, then you’ll just need to buy enough of the length that you want. If you want it any bigger around, you’ll need to buy twice the length that you need. So if you you want your skirt to be 22 inches long and need more than 40 inches around, you need to buy 44 inches in length. Make sense? My skirt is 25 inches long, so I needed at least 50 inches of length (because I needed mine bigger than 40 inches around to create a good gather) so I ordered I used just under 1.5 yards and had scraps left over.