Quilt Backing Calculator

Backing is cut larger than the quilt top so there is room to load it on a frame, and a seam allowance is lost wherever two pieces are joined. The calculator adds the margin on all four sides, then costs both ways of covering that cut size: lengthwise panels joined along their long edges, or crosswise strips joined across. On 42 in fabric a 68 × 80 in backing needs two pieces either way, and crosswise strips usually waste less; a 108 in wide back covers most throws in one piece. Yardage is the cut length times the number of pieces, rounded up to the next 1/8 yard for buying. Batting is cut to the same size as the backing. Directional prints, long-arm frame requirements and fabric shrinkage are not modelled. Everything runs locally in your browser with no storage, uploads or network access.