This calculator finds how many yards of fabric are needed for a set of pieces of the same size. It works out how many pieces fit across the width of the fabric, how many rows are needed for all the pieces, and then the length of fabric in yards. For 20 pieces of 8 by 10 inches on 42 inch fabric, five fit across, so four rows of 10 inches are needed, which is 40 inches, or about 1.1 yards.

Try turning the pieces to see whether they fit more efficiently the other way around, since a small change can save a lot of fabric. Pieces with a direction, such as stripes and one way prints, must all be cut the same way.

Add the seam allowance to each piece before you enter it, and allow a little extra for the selvage and for any flaws at the ends of the bolt. About ten percent more than the result is a sensible margin for most projects.

If you are cutting different sizes, work out each size separately and add the results, or lay the pieces out on paper to see how they fit together. Cutting the largest pieces first and fitting the smaller ones around them often wastes less.