Measure
Add working overage
Your selected allowance is added to all four sides of the finished quilt top. Use the number requested by your longarm quilter.
Plan before you cut
Quilt Backing Calculator
Turn your quilt size into a fabric purchase and cutting plan—yardage, panels, seams and the lower-waste layout included.
Calculate my backing
Runs in your browser. Your dimensions stay on your device.
Your backing plan
Buy, cut and piece with a plan
Backing size needed: —
Fabric to buy
—
Rounded up to the next ⅛ yard or 0.1 meter.
- Recommended layout
- —
- Panels to cut
- —
- Cut each panel
- —
- Seams to sew
- —
- Layout offcut
- —
Why this layoutComparing both directions…
Cutting diagram
Compare both seam directions
| Layout | Buy | Panels | Cut each | Offcut |
|---|
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How the backing calculation works
The calculator keeps the assumptions visible so you can adjust the plan before buying or cutting fabric.
Compare
Test both seam directions
We calculate panels with seams running vertically and horizontally, including the seam take-up between joined panels.
Round
Buy enough fabric
The lower-length valid layout is rounded upward to a practical purchase increment. Directional prints may change your choice.
EX
Queen quilt backing: a worked yardage example
For an 86 × 94 in top, use 4 in extra on every side and a ½ in seam allowance on each joined edge.
Required size
94 × 102 in
Add 8 in to each top dimension: 86 + 8 = 94, and 94 + 8 = 102. Overage is per side, not the total for both sides.
42 in usable WOF
3 panels, 7⅞ yd
Three 94 in cuts make horizontal seams. Joined coverage is 3 × 42 − 2 × 1 = 124 in, enough for the 102 in direction. Buy 282 ÷ 36 = 7.833 yd, rounded up to 7⅞ yd.
108 in usable width
1 piece, 2⅝ yd
A 94 in cut spans the 102 in direction without a piecing seam. 94 ÷ 36 = 2.611 yd, rounded up to 2⅝ yd. This assumes the measured usable width is actually 108 in.
With 42 in fabric, the alternate vertical-seam plan needs three 102 in cuts: 306 ÷ 36 = 8½ yd. The horizontal plan saves ⅝ yd of purchased length in this example, but it may rotate a directional print. Compare price per yard as well as length: wide-back and regular-width fabric are not priced identically.
Try these measurements in the backing calculator or plan the matching queen quilt binding.
Before you buy or cut
Measure usable fabric width after removing selvages. The estimate does not add extra for shrinking, straightening the ends, matching motifs or centering a seam. Ask your longarm quilter about backing overage and seam placement; those requirements override this example. See the complete calculation method and limitations.
Example arithmetic reviewed September 6, 2026. These are planning assumptions, not a standard queen quilt size.
02
Common quilt sizes
Presets are starting points, not standards. Measure the actual finished top whenever possible.
| Preset | Starting size | Typical use | Planning note |
|---|---|---|---|
| Baby | 36 × 48 in | Crib or play quilt | Often fits two regular-width panels. |
| Throw | 50 × 65 in | Sofa or lap quilt | Check whether a horizontal layout saves yardage. |
| Twin | 68 × 86 in | Single bed | Wide-back can remove piecing seams. |
| Queen | 86 × 94 in | Queen bed | Compare 42-inch and 108-inch fabric. |
| King | 104 × 94 in | King bed | Confirm extra frame-loading length. |
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Quilt backing questions
Practical checks to make before the first cut.
How much extra backing should I add around a quilt?
Many quilters add 2 to 4 inches per side. Longarm quilters often request 4 inches per side or more, so check with your quilter before cutting.
Is 4 inches of overage enough for longarm quilting?
Four inches per side is a common starting point, but frame, loading and trimming requirements vary. Use the allowance requested by your longarm quilter.
Should quilt backing seams run vertically or horizontally?
Either can work. Compare fabric length, print direction and seam placement. This calculator shows both layouts and recommends the one using less purchased length.
How wide is standard quilting cotton after selvages?
A 44-inch bolt often provides about 40 to 42 inches of usable width after selvages. Measure the actual fabric and enter its usable width.
Can I use 108-inch wide-back fabric?
Yes. Wide-back fabric often creates a one-piece backing for bed quilts. Enter the usable wide-back width to compare it with regular-width fabric.
Should I buy extra fabric beyond the calculated amount?
Consider extra for shrinkage, squaring, directional print matching, prewashing or mistakes. The calculator rounds purchases up but cannot see your specific print or pattern.
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Keep planning the quilt
Use the same finished dimensions for the next cut list.