Quilt Binding Length Calculator

Binding is the strip of fabric that encloses the raw edges where quilt top, batting and backing meet, and the quantity needed is a perimeter calculation with allowances. The base figure is 2 x (width + height); to that most quilters add 10 to 12 inches, roughly 2 to 3 inches for each mitered corner plus 6 to 10 inches of overlap to close the loop where the binding meets itself. That total is divided by the usable width of the fabric, normally 42 to 44 inches on the bolt minus about an inch of selvage, to give the number of cross-grain strips to cut, and strips times strip width divided by 36 gives yardage. Strip width is chosen from the finished result. Double-fold binding cut at 2.5 inches finishes at roughly half an inch on each face, 2.25 inches gives a narrower edge suited to baby quilts, and 2.75 to 3 inches suits thick batting. Strips are joined with a diagonal seam, which spreads bulk across a 45 degree line instead of stacking it on one crosswise seam, and each join consumes about one strip width. Straight-grain strips are fine on straight edges, but scalloped or curved edges need true bias, which stretches to follow a curve and requires roughly 20 percent more fabric. Measure the perimeter after quilting, since dense quilting can draw a top in by several percent.

Bound edges were not the original way American quilts were finished. Eighteenth and nineteenth century quilts commonly used a knife edge, with top and backing turned in and stitched closed, or brought the backing around to the front as a self-binding, both of which used no extra fabric at a time when cloth was expensive. Separate applied bindings, cut as strips and often in a contrasting print, became widespread through the nineteenth century as manufactured cotton grew cheap and as the bound edge proved far more durable, since the binding absorbs the abrasion that would otherwise wear through the quilt itself. The arithmetic in this calculator reflects two later industrial facts. Quilting cotton settled on a bolt width of about 44 or 45 inches, leaving roughly 42 inches usable after selvage and shrinkage, which is why strip counts are computed against that figure. And in 1979 the Japanese tool maker Olfa introduced the rotary cutter, which together with acrylic rulers and self-healing mats made accurate long strip cutting fast for the first time; strip-based binding and precut strip bundles are a direct consequence. The American quilt revival around the 1976 Bicentennial supplied the audience, and published patterns from that period onward standardised the 2.5 inch double-fold strip as the default.