How much overhang should I add for quilting?

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.

Why do I need to seam quilt backing?

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.

Should the backing seam run horizontally or vertically?

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.

Can I use a bedsheet for quilt backing?

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.

SewCalcs

Quilt Backing Calculator — Backing Fabric Yardage

Work out how much backing fabric you need with seaming for wide quilts.

Quilt Width

Finished width of your quilt top (cm)

Quilt Length

Finished length of your quilt top (cm)

Overhang Each Side

8-10cm typical for quilting

Fabric Width

Standard quilting cotton: 112cm

Fabric Price (optional)

Cost per metre of backing fabric (optional)

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

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Last updated: February 2026

All calculations are estimates. Always verify quantities before cutting or purchasing fabric.