QUILT BACKING GUIDE
Quilt backing, worked out clearly.
Use your finished quilt width and length to estimate backing yardage, panel count, and cut length. The free calculator compares ordinary quilting cotton with wide backing fabric and keeps the allowance visible.
Open the free quilt fabric calculator →
How the estimate works
The tool adds your backing allowance to both sides of each finished dimension. It then compares the required width with the usable width of the selected fabric. If one cut does not fit, it counts the straight panels needed across the quilt and multiplies by the cut length.
required width = finished width + 2 × backing allowance
required length = finished length + 2 × backing allowance
panels = ceiling(required width ÷ usable fabric width)
yardage = panels × required length ÷ 36The prototype reserves 4 inches from the nominal fabric width as a conservative trimming allowance. This is a planning convention for this tool, not a universal shop rule.
Worked example: 90 × 96 inches
With 4 inches of backing allowance on each side, the required backing rectangle is 98 × 104 inches. Using the tool's 40-inch usable run for 44-inch fabric takes 3 panels: 3 × 104 ÷ 36 = 8.67 yards. With 108-inch fabric, the tool uses a 104-inch usable run, so the same example takes 1 panel: 104 ÷ 36 = 2.89 yards.
The wider fabric may reduce seams and total yardage, but the better purchase depends on price, availability, print direction, and your quilter's requirements.
Check before buying
- Confirm whether your pattern gives a finished size or a pre-quilting size.
- Measure the actual usable width after selvages and any directional design constraints.
- Use the allowance recommended by your long-arm quilter or pattern designer when it differs from the default.
- Round up to the fabric shop's selling increment and allow for shrinkage, seams, and trimming.
This page documents the calculator's current assumptions. It is an estimate, not a cutting guarantee.
Read the backing size checklist → · Estimate binding fabric →