Quilt Backing Yardage Calculator
Calculate quilt backing yardage including overhang and the number of fabric widths you must seam together.
How it works
Backing size = (width + 2·overhang) × (height + 2·overhang) · Panels = ⌈backing width ÷ fabric width⌉ · Yardage = panels × backing length ÷ 36 (orientation chosen to minimize fabric)
Longarm and home quilters both need the backing to be larger than the quilt top so it can be loaded and basted — usually 3–4 inches of overhang on every side. When the backing is wider than the bolt you seam two or three full widths side by side, which multiplies the yardage. This calculator tests both seam orientations and reports whichever uses less fabric.
Worked example
A 60×80 in top with 4 in overhang needs a 68×88 in backing. On 42 in fabric, running panels the 68 in direction takes ⌈68 ÷ 42⌉ = 2 panels × 88 in = 176 in; the other way takes ⌈88 ÷ 42⌉ = 3 × 68 = 204 in. The 176 in option wins — about 4.89 yd.
Frequently asked questions
How much overhang should quilt backing have?
For home machine quilting 2–3 inches per side is plenty; for a longarm frame most shops ask for 4 inches on all four sides so there is fabric to clamp and load. Larger overhang is safer but adds yardage.
Which way should the backing seam run?
Run the seam whichever direction needs the fewest full widths of fabric — that is what this calculator picks. On a bed quilt that usually means one horizontal seam across the width rather than two vertical seams, saving a full length of fabric.
Can I use extra-wide backing fabric instead?
Yes. 108 in wide quilt backing avoids seams entirely for most bed sizes — set the usable fabric width to about 106 in (after trimming selvages) and the calculator will show a single panel.
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This calculator is for educational purposes. Double-check important results before acting on them.