Craft & baking
Quilt backing calculator
Compare backing layouts and turn your quilt measurements into fabric yardage.
- No sign-up
- Calculated on your device
02 / Your results
Before shop rounding: 176 in of fabric (≈ 4.889 yd).
| Layout | Panels × length | Fabric |
|---|---|---|
| Vertical | 2 × 88 in | ≈ 4.889 yd Buy 5 yd |
| Horizontal | 3 × 68 in | ≈ 5.667 yd Buy 5.75 yd |
Cut 2 panels, each 42 in wide × 88 in long. Join with 1 seam.
Target backing: 68 in × 88 in. Vertical seams run along the quilt’s length; horizontal seams run along its width.
The shorter layout may not suit directional prints or your quilter’s preferred seam placement.
How the calculation works
Measure the quilt top before adding backing. The quilt width and length of the quilt are the starting dimensions; add the extra backing to both sides of each dimension. Use the usable width of fabric after removing selvages, rather than the nominal width printed on the bolt.
For n panels of usable width F with seam allowance s on each joined edge, assembled width is nF − 2s(n − 1). Multiply the number of panels by the cut length, then divide inches by 36 for yards or centimetres by 100 for metres. This gives the amount of fabric before rounding to your shop’s purchase increment.
Compare both orientations before buying. A directional print, pattern matching, prewashing shrinkage or a longarm quilter’s seam requirements may change which layout is practical and how much extra fabric you need.
Try an example
A 60 × 80 inch quilt with 4 inches extra per side needs a 68 × 88 inch backing. With 42-inch usable fabric and ½-inch seam allowances, two 88-inch panels use about 4.89 yards, rounded up to 5 yards at ⅛-yard increments.
How to use this calculator
- Choose inches or centimetres. Enter the quilt width and height, then the extra backing required on each side by your quilting plan or longarm quilter.
- Enter usable fabric width after removing selvages, the seam allowance on each joined edge, and the purchase increment offered by your fabric shop.
- Select Calculate backing. Compare the two panel orientations and their cut lengths, then use the rounded purchase amount for the layout that suits your fabric and quilting plan.
Common questions
How do I calculate backing for quilts?
Measure the quilt top, add the required extra to each side, and compare that backing width with the usable width of fabric. Allow for the fabric consumed by each seam. Multiply the number of full-width panels by their cut length to get the total fabric length, convert it to yards or metres, then round up to the shop’s purchase increment. Check print direction and your quilter’s requirements before choosing a layout.
Is extra backing added to every side?
Yes. Entering 4 inches adds 8 inches to both quilt dimensions. A 60 × 80 inch quilt needs 68 × 88 inches before considering piecing seams. Confirm the required extra with your quilter; the example is not a universal longarm requirement.
How do fabric width and seams affect the result?
Use the width available after selvages are removed. Each seam consumes an allowance from both joined edges, so two 42-inch panels joined with a ½-inch allowance make an 83-inch-wide backing.
Should I always choose the layout using less fabric?
Check grain, directional prints and your quilter's seam preference first. This estimate uses full-width panels and does not add fabric for shrinkage, print matching or extra squaring. Purchase rounding does not guarantee enough for those additions.
Further reading: APQS: how to piece quilt backs