Quilt backing guide · updated August 2, 2026

How to calculate quilt backing yardage.

Add overage to the finished top, find the usable fabric width, compare panel directions and round purchase length upward.

Backing width = quilt width + 2 × overage
Backing length = quilt length + 2 × overage
Yardage = panels × panel cut length ÷ 36

1. Start with the finished quilt top.

Use the finished width and length after borders. If dimensions are unfinished, resolve them before calculating backing.

2. Add overage on every side.

Home-machine and longarm workflows may require different extra fabric. The calculator default is 4 inches per side, but your longarmer's instruction is the source of truth.

3. Use usable width after selvages.

Fabric labelled 42 or 44 inches may provide less usable width. YardageWise subtracts a visible selvage allowance instead of assuming every inch is available.

4. Compare vertical and horizontal panels.

Lengthwise panels use full backing length for every panel; crosswise panels use full backing width. The lower-yardage orientation is not automatically right for directional fabric.

5. Round upward and verify the cut plan.

The tool rounds to a quarter yard. Check panel count, cut length and pattern direction before buying.

Calculate your backing →