Quick Answer — How Much Fabric Does a Quilt Need?
Three separate calculations, and only one of them is straightforward.
Binding follows the perimeter. Total strip length is 2 × (width + length) plus an allowance for mitred corners and joining seams — 10 to 12 inches covers both. Divide by usable fabric width, round up for the strip count, and multiply by strip width for the yardage.
Backing needs to be larger than the quilt on every side so it can be loaded on a frame and trimmed square. Four inches of overhang per side, so eight inches on each dimension, is standard for a longarm.
Batting works the same way, usually with the same overhang.
Note the width you can actually use. Quilting cotton is sold as 42 inches, but selvages take roughly an inch, so 41 inches is what you cut from. For a 60 × 80 inch throw:
- Binding — 280 in perimeter plus 12 in allowance = 292 in needed, 8 strips at 2½ in wide, 0.63 yd
- Backing — 68 × 88 in finished, 2 panels seamed vertically, 4.89 yd (buy 5)
- Batting — 68 × 88 in from a 90-inch roll, 1 panel, 2.44 yd
Seaming that backing the other way would need 3 panels and 5.67 yd — three-quarters of a yard more for the same quilt.