Quilt Backing Calculator

Find the backing yardage for your quilt with standard or 108-inch wide-back fabric, and the best seam direction.

What this calculator assumes

Usable width: standard quilting cotton is sold 42 to 44 inches wide, but the calculator counts 42 inches usable after trimming the selvages. Wide-back fabric counts as 106 inches usable.
Overhang: 4 inches on every side by default, which means 8 inches added to both the width and the length. Change the box above to match what your quilter asks for. Quilting it yourself on a home machine? Many quilters use 2 to 3 inches per side instead. Enter that in the overhang box.
Seams: it checks seams down the length and across the width, and shows the one that uses less fabric.
Prewashing: shrinkage is not added. Treat the backing the same way as the quilt top, and buy extra if you plan to prewash.

Worked example, 60 x 72 in quilt, 42 in fabric, 4 in overhang: the backing needs to be 68 x 80 in. Seams down the length need 2 panels of 80 in (160 in, 4 1/2 yd). Seams across the width need 2 panels of 68 in (136 in), so buy 3 7/8 yd.

How it works

The backing is cut larger than the quilt top on every side (4 inches by default, which most longarm quilters ask for). The calculator works out how many fabric widths you need sewn together with the seams running down the length or across the width, and shows whichever uses less fabric. Ask your longarm quilter if they need more overhang.

Step-by-step explanation: How Much Backing Fabric Do I Need?

Quilt Backing Calculator

What this calculator assumes

How it works

Common sizes, worked out