Boneyard Tools

Quilt Backing Calculator for Yardage

Work out how much backing fabric a quilt needs before you shop. Enter the finished quilt width and length, the overhang you want on each side, and the usable width of your fabric. The tool returns the finished backing size, how many fabric widths you must seam together, and the total yards to buy.

How to calculate quilt backing

  1. Type the finished quilt width into the Quilt width field, in inches.
  2. Type the finished quilt length into the Quilt length field.
  3. Set Overhang per side to the extra backing you want, such as 4 inches.
  4. Set Fabric width to your usable width, 44 for standard cotton or 108 for wide backing.
  5. Read the backing size, widths to seam and total yards in the result cards.
  6. Press Copy estimate to save the backing size, seam count and yardage.

Examples

Throw quilt on standard cotton

Quilt 60 x 80 in, overhang 4 in, fabric 44 in
Backing 68 x 88 in, 2 widths, about 4.8889 yards

King quilt on standard cotton

Quilt 90 x 108 in, overhang 4 in, fabric 44 in
Backing 98 x 116 in, 3 widths, about 9.6667 yards

Same throw on 108 inch wide backing

Quilt 60 x 80 in, overhang 4 in, fabric 108 in
Backing 68 x 88 in, 1 width, about 2.4444 yards

Frequently asked questions

How much backing fabric do I need for a quilt?

Add the overhang to each side of the quilt top to find the backing size. If that backing width is wider than the fabric, seam full fabric widths side by side, then divide the total running length by 36 to get yards.

How much overhang should the backing have?

Longarm quilters usually ask for about 4 inches of extra backing on every side so they can load the quilt on the frame. For home machine or hand quilting 2 to 3 inches is often plenty. Confirm the number with your quilter before you cut.

Why does the backing have to be pieced?

Most quilting cotton is only about 44 inches of usable width, so any backing wider than that needs two or more full widths seamed together. The tool rounds the required widths up, since you cannot buy a fraction of a seamed panel.

Can I use extra-wide backing to avoid a seam?

Yes. Wide backing is sold in 108 inch widths, so set Fabric width to 108. Most bed quilts then need a single width with no seam at all, which is why a 60 by 80 inch quilt drops to about 2.4444 yards on wide goods.

How is the total yardage figured?

Yards equals the number of widths needed times the backing length, divided by 36 inches per yard. For a 68 by 88 inch backing needing 2 widths that is 2 times 88, which is 176 inches, divided by 36 to get about 4.8889 yards.

Should I round the yardage up when buying?

Yes. The result is the exact math, so round up to the next quarter or half yard at the shop and add a little for shrinkage from prewashing and for squaring the cut ends.

Does this include batting or binding?

No. It sizes only the backing. Batting wants a similar overhang and is a separate purchase, while binding yardage depends on the quilt perimeter and your strip width, which the seam-allowance and fabric-yardage tools can help with.

Does it assume seams run a certain direction?

It assumes full fabric widths are joined side by side to reach the backing width, with the seams running the length of the quilt. That is the standard vertical-seam layout and it ignores the small amount of fabric lost inside each seam.

Is anything I enter sent to a server?

No. The calculation runs entirely in your browser with simple arithmetic, so your quilt measurements never leave your device.

Learn more

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