Quilt backing calculator
A queen size quilt typically needs about 8 1/4 yards of 42" fabric, or just 2 3/4 yards of 108" wide backing. Enter your exact quilt size below to get your yardage, panel cuts, and seam placement in seconds.
You will need
How much backing fabric do I need?
Your backing needs to be larger than your quilt top on all four sides. If you are sending your quilt to a longarm quilter, plan on at least 4 extra inches per side (8 inches total in each direction) so the backing can be loaded onto the frame. Quilting it yourself on a home machine? You can get away with 2 to 3 inches per side.
Once you know the backing size, the yardage depends on your fabric width. Standard quilting cotton is 42" to 44" wide, so most quilts need two or three panels sewn together. Extra wide 108" backing usually covers the whole quilt in a single panel with no seams at all.
Backing yardage for common quilt sizes
These figures use the longarm standard of 4" overhang per side. Your quilt may differ from these typical dimensions, so use the calculator above for your exact measurements. Wide backing figures assume the fabric can be rotated sideways (railroaded) when that saves yardage; if your backing is a directional print, use the seam direction setting above instead.
| Quilt size | Typical dimensions | 42" fabric | 108" wide backing |
|---|---|---|---|
| Crib | 36" x 52" | 2 1/2 yards | 1 1/4 yards |
| Throw | 50" x 65" | 3 1/4 yards | 1 3/4 yards |
| Twin | 70" x 90" | 5 1/2 yards | 2 1/4 yards |
| Full | 84" x 90" | 7 3/4 yards | 2 3/4 yards |
| Queen | 90" x 95" | 8 1/4 yards | 2 3/4 yards |
| King | 110" x 95" | 8 3/4 yards | 3 1/2 yards |
Should backing seams run vertical or horizontal?
Whichever direction uses less fabric, usually. The calculator checks both and recommends the cheaper one. There are two exceptions worth knowing. If your backing fabric is directional (a print with an obvious up and down), the seams must run so the print stays upright. And some longarm quilters prefer horizontal seams because they put less stress on the seam while the quilt is rolled on the frame. When in doubt, ask your longarmer; they will be delighted you asked.
Sources and methodology
The math: backing width = quilt width + 2 x overhang, and the same for length. Panels = the backing dimension divided by usable fabric width, rounded up. Usable width assumes 2" lost to selvages. Total yardage = panels x panel length, divided by 36, then rounded up to the next quarter yard. The 4" per side overhang default follows standard longarm loading requirements. Formulas are cross-checked against published quilting references before every update.
Backing questions, answered
At least 4 inches on every side if a longarm quilter will be doing the quilting, which means 8 inches wider and 8 inches longer overall. That extra fabric is what gets clamped to the frame. For quilting on your own machine, 2 to 3 inches per side is enough.
You can, but choose carefully. High thread count sheets are densely woven and can be hard to needle, which causes skipped stitches on longarm machines. Many longarmers will not accept sheets for this reason. A 100% cotton sheet with a moderate thread count works better than a crisp percale, but quilting cotton or wide backing is the safer choice.
Match the backing to the top: if you prewashed your quilt top fabrics, prewash the backing too. Cotton can shrink up to 3 to 5 percent, so if you prewash, buy about a quarter yard extra to be safe. If you love the crinkly look after the first wash, skip prewashing both.
Extra wide quilting cotton made specifically for backings. Because it is 108" wide, most quilts up to king size need only a single panel and zero seams. It costs more per yard than standard cotton, but you need far fewer yards, so the total cost is often similar and you save an evening of piecing.