Fabric Piping Calculator

Cut bias strips as wide as the cord's circumference plus two seam allowances. For 100 inches of piping with 1/4 inch cord and 0.5 inch seam allowances, you need 1.79 inch strips, cut from a 14 inch square of fabric.

Fabric Piping Calculator

Enter how much piping you need and your cord size
Start with a
0
inch square of fabric

Bias Strip Width by Cord Size

Strip width is the cord's circumference (pi times the diameter) plus two 0.5 inch seam allowances. The square is what you need for 100 inches of piping with a 6 inch joining allowance.

Cord diameterBias strip widthFabric for 100 in of piping
1/8 in1.39 in12.5 in square
3/16 in1.59 in13 in square
1/4 in1.79 in14 in square
3/8 in2.18 in15.5 in square
1/2 in2.57 in17 in square
3/4 in3.36 in19 in square

How the Continuous Bias Method Works

Instead of cutting and joining many short bias strips, you cut one square, turn it into a tube and cut a single long strip in a spiral. The strip's length times its width equals the square's area, so the square's side is the square root of strip length times strip width.

  1. Cut a square of the size the calculator gives you.
  2. Cut it in half on the diagonal and sew the two triangles into a parallelogram.
  3. Mark lines parallel to the bias edge, one strip width apart.
  4. Sew the ends into a tube, offset by one strip width, and cut along the marked line in one continuous spiral.
Tip: The seams and the offset use a little fabric, which the rounded-up square and the joining allowance cover. For very long runs, add a few inches more.

Frequently Asked Questions

How wide should bias strips be for piping?
Wrap a tape measure around the cord to get its circumference, then add two seam allowances. For 1/4 inch cord and 0.5 inch seam allowances, that is 1.79 inches.
How much fabric do I need for piping?
For 100 inches of piping with 1/4 inch cord, you need about 106 inches of 1.79 inch bias strip, which you can cut from a 14 inch square. That is less than half a yard of most fabrics.
How long a bias strip does a square of fabric make?
Divide the square's area by the strip width. An 18 inch square gives 324 square inches, so 2 inch strips come to about 162 inches, minus a little for the seams.
Do piping strips have to be cut on the bias?
For curves and corners, yes. Bias strips stretch and bend smoothly around cushions and seat edges. For straight runs you can cut strips on the straight grain, which uses less fabric.

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