108-Inch Quilt Backing: Yardage and Fit Guide

Measure the backing target before choosing fabric

Write down the actual pressed top width and length. Ask the person quilting it how much extra fabric they need on every side. This guide uses 4 inches per side for examples, following the Missouri Star backing method; it is not a universal longarm requirement. If your quilter asks for a larger margin, use that value instead.

• Target width = top width + 2 × side allowance.
• Target length = top length + 2 × end allowance.
• Keep backing and batting requirements separate; neither is the finished quilt size.

Two directions, one fit test

Call the measured usable fabric width U and the backing target W by L. If U is at least W, cut a length L. If U is at least L, you may instead cut a length W. When both fit, the shorter length uses less fabric. When neither fits, one unpieced length cannot cover the target: choose wider fabric or plan a pieced backing.

A directional print can rule out the cheaper rotation. Check which way the motif will face on the finished quilt and confirm that the longarm setup allows your chosen orientation. Yardage alone cannot decide these details.

Worked queen example: why the width label matters

For an example 90 by 100-inch top, adding 8 inches to each dimension gives a 98 by 108-inch backing target. Assume the fabric actually measures 106 usable inches. The 98-inch side fits across it, so the required cut length is 108 inches. Divide 108 by 36 to get 3 yards. The 108-inch side does not fit across 106 usable inches, so rotating it to buy only 98 inches would leave the backing short.

If you instead measure at least 108 usable inches and the print may turn, the 108-inch side can run across the fabric. The required length is then 98 inches. A shop that cuts in eighth-yard increments rounds this to 99 inches, or 2 3/4 yards. These are geometric minimums, not a promise that a nominal 108-inch bolt will fit either plan.

Minimum yardage chart for measured 106-inch width

These examples assume 4 inches extra on each side, 106 inches of measured usable width, a print that may rotate, and purchase increments of 1/8 yard. They exclude extra length for squaring, print matching and future shrinkage. Recalculate if any assumption changes.

Turn the minimum into a purchase plan

Add the extra length you need for squaring and print alignment before rounding to the shop’s increment. If buying before washing, account for expected shrinkage in both directions; length allowance does not fix insufficient width. Use a sample measurement rather than an assumed percentage. The fabric shrinkage calculator linked here separates those two dimensions.

For eighth-yard cuts, divide the required inches by 4.5, round up to a whole number, and divide that count by 8 for yards. If your shop cuts only quarter yards, use 9-inch increments instead. Ask the seller about the width and care instructions before ordering, then check the delivered fabric before cutting.

• Confirm the quilter’s margins and acceptable seam direction.
• Measure the usable width, not the printed selvage-to-selvage label.
• Mark the print direction on a sketch of the quilt.
• If the fit is exact, add a practical margin or choose a wider backing.

Common questions

Is 108-inch backing wide enough for a king quilt?

Not automatically. A 108 by 108-inch top needs a 116 by 116-inch backing with 4 inches extra on every side. A single length of nominal 108-inch fabric cannot cover that target. Check a wider fabric or a pieced plan with your quilter.

How many yards of 108-inch backing for a queen quilt?

Use the actual top size, not the bed label. In this guide’s 90 by 100-inch example, 106 usable inches of fabric width require a 108-inch length, or 3 yards before extra allowances. A different top, margin or print direction changes the answer.

Can I use the short side of my quilt for the purchased length?

Only when the other backing dimension fits across the measured usable fabric width and the print can rotate. Include the quilter’s margins before testing the fit.