Quilt backing must be larger than the top, with a few inches of overhang on every side for longarm quilting. This formula sizes the panels and yardage.
Yards = A × ((L + 8) ÷ 36)
What the terms mean
| Symbol | Meaning |
|---|---|
| Yards | Backing yardage needed |
| A | Panels across (width + 8) ÷ 42 |
| L | Quilt length, in inches |
| 8 | Total overhang, 4 in per side |
| 42 | Usable fabric width, in inches |
Worked example
A 60 by 80 in quilt needs (60 + 8) ÷ 42 = 2 panels, each (80 + 8) ÷ 36 = 2.44 yd, so about 4.9 yards.
Mind the seam direction. Piecing two panels with a vertical or horizontal seam changes the yardage. Choose the orientation that uses less fabric.
See the Quilt Backing Calculator and the Backing.