Binding Yardage, Explained
Binding is the one number quilters most often guess — and guess short. The real formula is three short steps, and every part of it has a reason.
Step 1: The perimeter of the quilt top
Binding wraps the edges of the finished quilt top — not the oversized backing, which gets trimmed away. So binding length starts from the top's perimeter:
Perimeter = 2 × (top width + top length)
For a 60" × 80" quilt: 2 × (60 + 80) = 280 inches.
Step 2: Add 10 inches — and why
Binding needed = perimeter + 10" → 280 + 10 = 290 inches.
That 10" is not superstition. It covers three real costs:
- Mitered corners. Each corner folds extra fabric into the miter; four corners eat several inches beyond the straight perimeter.
- The final join. Joining the two binding tails (usually on a diagonal) overlaps the ends — that overlap comes out of your strip, not your quilt.
- Tails and handling. You need a few loose inches at the start and end to maneuver the join under the needle.
Skip the 10" and you discover the shortage at the last corner, with the quilt half-bound. It is the cheapest insurance in quilting.
Step 3: Strips and yardage
Binding strips are cut across the width of your fabric, so each strip gives you one fabric-width of binding:
- Strips = binding length ÷ fabric width, rounded up. 290 ÷ 42 = 6.9 → 7 strips. (A strip cannot give more than its width; diagonal seams joining strips cost a little length, which the +10" already absorbed.)
- Yardage = strips × strip width. 7 × 2.5" = 17.5" of fabric → 17.5 ÷ 36 = 0.486 yd → buy ½ yard.
2.25" vs 2.5" strips
| Strip width | Finished look | Same 60" × 80" quilt |
|---|---|---|
| 2.5" | A slightly fuller binding; the common default, forgiving for beginners | 7 strips → 17.5" → ½ yd |
| 2.25" | A snugger, tighter binding many experienced quilters prefer | 7 strips → 15.75" → ½ yd (⅜ yd is 13.5" — not enough) |
Notice the trap: narrower strips do not always save fabric, because the strip count rarely changes — length drives the count, width only scales the yardage. Both widths land on ½ yard here. Run your own size in the calculator before assuming.
Common ways binding math goes wrong
- Using the backing dimensions. The backing is 8" bigger in each direction at a 4" margin — figuring binding from it overstates length but, worse, confuses every later step.
- Forgetting the join. Perimeter alone is never enough; corners and tails are real.
- Dividing by 44 because "fabric is 44 wide." Your bolt might be 42". On a big quilt that 2" difference can change the strip count.
- Buying exactly the computed yardage for a directional or fussy print. The math assumes plain fabric; add a cushion if you are matching stripes or a border print.