A few useful things to know
How to use this binding calculator
Straight-grain, double-fold binding is cut in strips across your fabric. The perimeter is only the starting point: each join shortens the finished length. This tool counts those losses separately from your corner and closing allowance.
- Enter the finished quilt width and length after adding borders.
- Choose the cut strip width your pattern or binding method needs. The planned visible width is a check, not a guarantee of the finished fold.
- Choose diagonal or straight strip joins. Seam allowance is per piece at a straight join; diagonal joins overlap by one full strip width.
- Cut the stated number of full-width strips, join, press and fold. Check the binding against the quilt before attaching.
A worked example
A 60 × 80 inch quilt has a 280-inch perimeter. Add 12 inches: the working length is 292 inches. From 42-inch fabric, eight 2½-inch strips joined diagonally yield 318½ inches after seven joins. The strips use 20 inches off the bolt, or 0.556 yards. Buy ⅝ yard when the shop cuts in eighths.
The method behind the result
Working length = 2 × (width + length) + extra. If join loss is j and fabric width is F, n strips give nF − (n − 1)j. Select the smallest whole n that reaches the working length. For a 45° strip join j is the cut strip width; for a straight join j = 2 × seam allowance. Fabric length = n × cut strip width.
What this plan assumes
This is a straight-grain, double-fold strip plan for a rectangular quilt. It does not calculate continuous bias binding or curved edges. Extra length covers corners and the final closing join; it is additional to the loss at strip-to-strip joins. Batting thickness and attachment technique affect the visible binding width, so test a short sample.
Common mistakes to avoid
- Treating all the unjoined strip lengths as usable binding.
- Using the desired visible binding width as the cut strip width.
- Including borders in the fabric plan but leaving them out of the quilt perimeter.
- Applying a straight-grain plan to scalloped or curved edges.