First measure your quilt top to find the length and width in inches. Since every machine and every quilter will sew slightly different quarter inch seam, you must actually measure your top instead of relying on the finsihed measurements given in your pattern. The first step is to multiply your length in inches times your width in inches. Then follow the formula below substituting you dimensions and the quoted pricing.
Square feet:
80" x 90" = 7200 sq.in.
7200 sq. in. ÷ 144 sq.in. = 50 sq.ft
50 sq.ft. x $3.50 = $175.00