Continuous Bias Binding Calculator
Enter how much bias you need and your strip width. The calculator gives the size of square to cut for the continuous bias method, rounded up to an easy ruler measurement, and the fabric to buy.
The formula
Worked example. 290 in of 2.5 in binding with 10% extra needs √(319 × 2.5) ≈ 28.2 in, so cut a 28.5 in square, which yields about 325 in of bias.
How to use it
- Measure the edge you are binding. For a quilt or tablecloth this is the perimeter, 2 × (width + length).
- Enter the strip width: 2.5 in (6 cm) for double-fold quilt binding, or about 2 in (5 cm) for 1/2 in double-fold bias tape.
- Keep about 10% extra for joining the tube and finishing the ends.
- Cut the square, slice it on the diagonal, sew it into a tube offset by one strip width, and cut the continuous strip.
Questions
Why use continuous bias instead of cutting strips?
Cutting single bias strips and joining them means many short seams. The continuous method turns one square into a long strip with only two seams, and wastes less fabric.
When do I need bias binding?
Use bias for curved, scalloped or rounded edges, and for piping, because bias stretches around curves without puckering. Straight edges are fine with straight-grain strips, which the quilt binding calculator covers.
Can I use a rectangle instead of a square?
Yes, the method works with rectangles too, and the yield is roughly width × length ÷ strip width. A square is simplest to mark, which is why the calculator uses one.