Enter your quilt size and strip width. The calculator adds 10 in to the perimeter for the corners and the final overlap, allows for the length each diagonal join uses, then tells you how many strips to cut and how much fabric they take.
Worked example: binding a throw quilt
A 50 x 65 in throw bound with 2 1/2 in double-fold strips.
- Perimeter: 2 x (50 + 65) = 230 in.
- Add 10 in for the corners and the closing overlap: 240 in of binding.
- Each strip gives 42 in less about one strip width for its diagonal join: 42 - 2 1/2 = 39 1/2 in.
- Strips: 240 / 39 1/2 = 6.08, rounded up to 7 strips.
- Fabric: 7 strips x 2 1/2 in = 17 1/2 in, which rounds up to 1/2 yd.
Result: Cut 7 strips 2 1/2 in wide: 1/2 yd of fabric.
How binding is calculated
- Perimeter = 2 x (quilt width + quilt length).
- Binding length = perimeter + extra (10 in by default) for the mitred corners and the overlap where the ends meet.
- Usable length per strip = usable fabric width (42 in) - strip width, because a 45-degree join between two strips uses about one strip width.
- Strips = binding length / usable length per strip, rounded up. This guarantees the joined strip covers the whole binding length.
- Fabric = strips x strip width, then divided by 36 and rounded up to the next 1/8 yard.
Assumptions
- Strips are cut on the straight grain across the width of fabric. Bias binding for curved edges needs more fabric and is not covered.
- 2 1/2 in is a common double-fold strip width; 2 1/4 in gives a narrower binding. Enter the width your pattern calls for.
- Usable width is 42 in after trimming selvages. If your fabric is narrower, enter its width.
How to cut and prepare double-fold quilt binding
Cut straight-grain strips across the width of fabric, join them and press them into double-fold binding.
- Use the calculator to find the number of strips, then cut that many strips across the width of fabric at your chosen width.
- Trim the selvages, lay two strip ends right sides together at a right angle and sew diagonally from corner to corner.
- Trim the seam allowance to 1/4 in and press it open. Repeat until all strips form one long strip.
- Press the whole strip in half lengthwise, wrong sides together, so the raw edges meet.
- Sew the raw edges to the front of the quilt with a 1/4 in seam, mitring each corner, then fold the binding to the back and stitch it down.
Frequently asked questions
How many binding strips do I need for a queen quilt?
For a 90 x 108 in queen, the perimeter is 396 in. With 10 in extra that is 11 strips of 42 in fabric, or 7/8 yd at 2 1/2 in wide.
What width should I cut binding strips?
2 1/2 in is the most common width for double-fold binding and suits most cotton quilts with standard batting. Many quilters use 2 1/4 in for a slimmer binding, or wider strips for thick batting.
Why add 10 inches to the perimeter?
Each mitred corner uses a little length, and you need an overlap to close the binding. 10 in covers that on most quilts; add more if you like a longer tail to work with. The diagonal joins are counted separately, one strip width per strip.
Can I use this for bias binding?
No. Bias strips are cut diagonally, so their length per strip changes with the size of the fabric piece. This calculator covers straight-grain strips cut across the width of fabric.