How to calculate quilt binding
Binding length = 2 × (width + length) + 12"
Strips = binding length ÷ 40", rounded up
Fabric = strips × strip width, rounded up to the next 1/8 yard
Use the finished size of the quilt, including any borders. The extra 12" covers the four mitered corners and joining the ends; 40" is a safe usable length per strip once you trim the selvages and join the strips with diagonal seams.
Worked example: 60" × 72" quilt
- Perimeter: 2 × (60 + 72) = 264". Add 12" for 276".
- Strips: 276 ÷ 40 = 6.9, so cut 7 strips of 2 1/2".
- Fabric: 7 × 2 1/2" = 17 1/2", so buy 1/2 yard.
Bias binding
For curved or scalloped edges, cut continuous bias binding from one square of fabric. The square side is the square root of (binding length × strip width), plus a margin:
Square side = √(binding length × strip width) + 1"
For the example above, √(276 × 2.5) ≈ 26.3", so start with a 27 1/2" square: 7/8 yard.
Choosing a strip width
| Strip width | Best for |
|---|---|
| 2 1/4" | Thin batting, a narrow finished edge |
| 2 1/2" | Standard double-fold binding, most quilts |
| 2 3/4"–3" | Thick, high-loft or wool batting |