How much backing fabric for a quilt? (by size)
Need a quick estimate before you measure? The table below shows roughly how much backing fabric common quilt sizes need, using standard 42-inch quilting cotton with 4 inches of overage on every side, using the same defaults as the calculator. Your pattern's finished size may differ, so plug your real numbers in above for an exact answer.
| Quilt size | Top size (in) | Backing yardage* | Panels |
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| Crib / Baby | 36 × 52 | 2½ yd | 2 |
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| Throw / Lap | 50 × 65 | 3¼ yd | 2 |
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| Twin | 70 × 90 | 5½ yd | 2 |
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| Full / Double | 85 × 108 | 7¾ yd | 3 |
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| Queen | 90 × 108 | 8¼ yd | 3 |
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| King | 108 × 108 | 9¾ yd | 3 |
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*Standard 42" wide quilting cotton, 4" overage per side, pieced the thriftier direction and rounded up to the nearest ⅛ yard. With 108" wide-back fabric most of these need just a single seamless panel.
How to calculate quilt backing yardage
The backing has to be bigger than the quilt top so there's something to grip when you baste, quilt, and square up. Add your overage to both the width and the length, then figure out how many fabric-width panels it takes to cover that area and how long each panel must be. Because seams can run either direction, the calculator works out both vertical and horizontal piecing and recommends whichever wastes less fabric. Open "How it's calculated" above to see the exact formula.
A note on batting and wide backing
Whatever your backing measures, cut your batting to the same generous size, a few inches larger than the quilt top on every side. If you'd rather avoid seams altogether, switch the usable fabric width to 108 inches (274 cm) for extra-wide quilt backing. Most throws and beds then fit in one panel with zero piecing.
Common questions
How much backing fabric do I need for a quilt?
You need fabric that covers the quilt top plus a few inches of overage on every side, pieced into as many fabric-width panels as it takes. As a rough guide at 42-inch quilting cotton: a throw needs about 3¼ yards, a twin about 5½, a queen about 8¼, and a king about 9¾. Enter your exact top size above for a precise figure, since quilt dimensions vary by pattern.
How much backing fabric do I need for a queen-size quilt?
A queen quilt top of about 90 × 108 inches needs roughly 8¼ yards of standard 42-inch backing fabric pieced into three panels, or a single panel of 108-inch wide-back fabric. Enter your exact top size above for a precise number, as quilt dimensions vary by pattern.
How much overage should I add to quilt backing?
4 inches (10 cm) per side is the standard home-quilter allowance and the default in this calculator. If you're using a long-arm quilting service, ask them first, as many require 4–6 inches on every side to load the quilt onto their frame without running short.
Why do I need extra fabric beyond the quilt top?
The backing has to be bigger than the quilt top so there's something to hold onto while you baste the layers, quilt them together, and square up the finished quilt. The extra also absorbs the slight shifting that happens as the quilting stitches pull the layers in. Cutting the backing exactly to the top size almost always leaves you short on at least one edge.
Should I piece quilt backing with vertical or horizontal seams?
The calculator compares both and picks whichever uses less fabric. Vertical seams (running top-to-bottom of the quilt) work well for most lap and bed quilts. Horizontal seams can be more efficient for very wide quilts that are shorter than they are wide.
What is WOF (width of fabric)?
WOF is the usable width of fabric after washing, pressing, and trimming selvages. Standard quilting cotton is typically 40–42 inches (100–107 cm). Wide backing fabric runs 108 inches (274 cm). Enter that number to see how it changes the panel count.
Should I pre-wash quilt backing fabric?
Most quilters recommend pre-washing to prevent post-quilt shrinkage. Cotton backing fabric can shrink 3–5% when washed for the first time. If you plan to skip pre-washing, add an extra ⅛–¼ yard as a safety margin.
Can I use 108-inch wide quilt backing fabric?
Yes: enter 108 (or 274 cm) as the usable fabric width. Many quilts will only need one panel of wide-back fabric, which eliminates seams entirely. The calculator will show "1 panel, 0 seams" when the backing fits in a single width.
How do I calculate quilt backing yardage by hand?
Add your overage to both dimensions (top size + 2 × overage). Divide the backing width by your fabric width and round up to get the number of panels, then multiply the panel count by the backing length. Divide that total by 36 for yards and round up to the nearest ⅛ yard. This calculator does the same steps and also checks horizontal seams in case they use less fabric.