Hobbies, Pets, Food & Lifestyle

Quilt Backing Calculator

Estimate the total continuous yardage of fabric required for the backing of your quilt, accounting for necessary overhang and seams.

in
in
in
Estimated Yardage
4
Layout SuggestionHorizontal Strips

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Planning Your Quilt Backing

Selecting and calculating the backing for a quilt is often an afterthought, but it requires careful geometric planning. Because the 'quilt sandwich' (top, batting, and backing) is loaded onto a machine or basted by hand, the backing must be significantly larger than the quilt top to allow for shifting and mounting.

The 'Overrun' Requirement

Standard quilting practice requires a 4-inch overrun on all four sides of the quilt. This means if your quilt top is 60x80 inches, your backing must be at least 68x88 inches. This extra fabric provides 'handles' for longarm quilting machines and ensures the needle never accidentally misses the backing fabric during the quilting process.

The difficulty in backing arises from standard fabric widths:

  • Standard Quilting Cotton: 42-44 inches wide. Most quilts will require two or more lengths of this fabric to be seamed together.
  • Wide-Back Fabric: 108 inches wide. These are specifically designed for quilting and can cover most large quilts in a single, seamless piece.

The Formula

We calculate the required yardage by determining how many full-width strips are needed to cover the width of the quilt, then multiplying by the length.

Yards = [Ceil( (QuiltWidth + 8) / BackingWidth ) * (QuiltLength + 8)] / 36

Where:
QuiltWidth, QuiltLength=
The dimensions of the finished quilt top
8=
The mandatory 4-inch buffer on all sides (4 + 4)
BackingWidth=
The width of the fabric bolt you are using (e.g. 44 or 108)

Seam Orientation

When piecing a backing, you should decide between vertical or horizontal seams. Vertical seams (running parallel to the length of the quilt) are generally preferred for aesthetic reasons and for ease of loading onto a longarm frame.

Frequently Asked Questions

This is primarily for safety. During the quilting process, the top and batting can shift slightly. If your backing is the exact same size as the top, any minor misalignment will result in the back of the quilt having raw batting showing through. For longarmers, this extra fabric is also used to clamp the backing to the frame.

While possible, it is generally discouraged. Bed sheets have a much higher thread count than quilting cotton. This makes them very dense, which can cause 'skipped stitches' and needle breakage on quilting machines. Additionally, the weave of a sheet differs from quilting cotton, which can cause the quilt to pucker or drape oddly after washing.

Backing seams should be pressed open rather than to one side. Because the seam will be sandwiched inside the quilt, pressing it open reduces bulk and ensures the quilting needle can pass through the seam area without deflection or resistance.

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