Question 1

What is continuous bias binding?

Accepted Answer

Continuous bias binding is made from a single fabric square. You cut the square once on the diagonal into two triangles, sew them together into a parallelogram, mark parallel lines at your cut-width spacing, sew the parallelogram into a tube with the marks offset by one strip width, then cut around the tube to produce one long continuous strip — all on the bias (45° to the grain). Bias binding stretches around curves and is stronger than straight-grain binding because the folds are not on the same threads.

Question 2

What cut binding strip width should I enter?

Accepted Answer

Enter the width of the strip BEFORE folding — the width you actually cut. 2.5″ is the standard cut width for double-fold (French-fold) quilt binding and is the default. Use 2.25″ for a slightly narrower finish, or wider (2.75″–3″) for thicker quilts or wider finished binding. The cut width depends on your binding construction and personal preference, so it is an input, not something derived from a finished width.

Question 3

How is the bias square size calculated?

Accepted Answer

The square must yield enough strip length. The continuous-bias yield from a square of side S is approximately S² ÷ cut width (the square's area divided by the strip width). Solving for the length you need gives a THEORETICAL minimum square of √(length needed × cut width). You cannot easily cut a fractional square, so the PRACTICAL starting square is rounded UP to the next ½″, which guarantees the yield is at least the length you need.

Question 4

How is the binding length needed determined?

Accepted Answer

Total length = quilt perimeter + join/overlap allowance. The perimeter is 2 × (width + length). The join allowance (default 12″) covers the diagonal seam where the binding ends meet plus a little overlap for trimming.

Question 5

How is the fabric yardage calculated?

Accepted Answer

The practical bias square of side S is cut from S linear inches of width-of-fabric (assuming S is no wider than your fabric width). Yardage = S ÷ 36, rounded up to the next 1/8 yard. If the square is wider than your fabric, the calculator warns you to use wider fabric or piece the square.

Continuous Bias Binding Calculator — Bias Square & Yardage

What this calculator determines

Related calculators

Examples

50″ × 50″ quilt, 2.5″ cut strip, default 12″ join (200″ perimeter)

75″ × 75″ quilt, 2.5″ cut strip, default 12″ join (300″ perimeter)

Assumptions & Conventions

Frequently asked questions