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Quilt Backing Calculator — Backing Fabric Yardage
Work out how much backing fabric you need with seaming for wide quilts.
How We Calculate This
Backing dimensions are calculated by adding overhang allowance to each side of the quilt for quilting grip. When the backing is wider than your fabric, panels are joined and each seam consumes a seam allowance from both joined edges, so the panel count accounts for that loss.
The formula
Backing width = Quilt width + (Overhang × 2)
Backing length = Quilt length + (Overhang × 2)
Usable width = Fabric width − Selvedge trim
Panels = smallest n where (n × Usable width) − ((n − 1) × 2 × Seam allowance) ≥ Backing width
Total fabric = Panels × Backing length
Frequently Asked Questions
Add 8-10cm on each side for quilting overhang. This gives your long-arm quilter or quilting frame room to grip the backing. The excess is trimmed after quilting.
Most quilting cotton is 112cm wide. For quilts wider than about 110cm, you need to seam two or more panels of backing together. Wide backing fabrics (274cm) are available but cost more.
Either works. Vertical seams use less fabric for most quilts. Some quilters prefer horizontal seams to avoid a seam running down the centre. This calculator assumes vertical seams.
Yes, but sheets have a higher thread count making hand quilting difficult. They work well for tied quilts or machine quilting. Make sure the sheet is large enough with overhang for your quilting method.
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Last updated: February 2026
All calculations are estimates. Always verify quantities before cutting or purchasing fabric.