Quilt Backing Calculator
Calculate how much backing fabric you need and how to piece panels together.
Tip: Use 4" overhang for machine quilting, 6-8" for long-arm quilting.
How to Use
- Enter your finished quilt top width and length in inches.
- Choose your backing fabric width (44" is standard quilting cotton; 108" is wide backing).
- Set your desired overhang — typically 4" per side for machine quilting.
- Click Calculate Backing to see yardage and piecing instructions.
Common Quilt Backing Reference
| Quilt Size | 44" Fabric | 108" Fabric | Panels (44") |
|---|---|---|---|
| Baby (36"×45") | 1.5 yds | 1.5 yds | 1 |
| Throw (60"×80") | 5 yds | 2.5 yds | 2 |
| Full (80"×90") | 7.5 yds | 3 yds | 3 |
| Queen (90"×108") | 9 yds | 3.5 yds | 3 |
| King (108"×108") | 10 yds | 3.5 yds | 3–4 |
Piecing Tips
When piecing 44" backing panels, press seams open to reduce bulk. Place seams off-center so they don't run down the middle of your quilt. For a horizontal seam, cut two pieces each half the total length plus a few inches for seam allowance.
About this Quilt Backing Calculator
Backing fabric needs to be larger than the quilt top on every side, since the quilting process can shift the layers slightly and the quilt is trimmed to its final size only after quilting is finished. This calculator adds your chosen overhang to each side of the quilt top, then figures out how many panels of your fabric width are needed to cover that larger size — 44" fabric almost always needs piecing for anything bigger than a baby quilt, while 108" wide backing often covers a quilt in a single piece.
Piecing seams eat a little of your overhang
When 44" fabric needs multiple panels, the seam allowance used to join them reduces the usable width slightly — the calculator accounts for a 1" loss per join, but if you use a wider seam allowance for stability, re-check that your pieced backing still covers the full overhang on every side before quilting. See the Quilt Batting Calculator to size batting for the same quilt.