BACKING SIZE CHECKLIST
How much fabric do you need for quilt backing?
Start with the finished quilt size, then add an allowance on every side. A calculation based only on the finished dimensions can be too small after quilting, trimming, seams, or shrinkage.
A repeatable estimate
- Write down the finished width and length.
- Add the backing allowance to both sides of both dimensions.
- Compare the required width with the usable width of the fabric.
- If the fabric is narrower, count the panels and multiply by the cut length.
- Round up when purchasing and confirm the result with your pattern or quilter.
Run your dimensions through the free calculator →
Example: 90 × 96 inches
With 4 inches on each side, the required rectangle is 98 × 104 inches. The calculator's conservative 40-inch usable run for 44-inch fabric requires 3 panels, or 8.67 yards. Its 104-inch usable run for 108-inch fabric requires 1 panel, or 2.89 yards.
Those values describe this tool's straight-panel estimate. They do not promise an optimized layout or the amount a particular shop will request.
Why answers differ
Two quilters can recommend different amounts because they may use different allowances, usable widths, seam plans, quilting machines, or fabric layouts. Wide backing can avoid seams, while pieced backing can use smaller pieces already on hand. Price, availability, print direction, and personal tolerance for trimming all matter.
Before you purchase
- Check the pattern's definition of finished size.
- Ask the quilter how much extra they need on each side.
- Measure usable width after selvages and account for directional designs.
- Allow for shrinkage and buy the shop's next whole or half-yard increment.
This guide explains the prototype's assumptions so you can adjust them. Your pattern designer or quilter's specification takes priority.