|Fabric cut on the bias has more stretch than fabric cut on the straight of grain. For this reason, bias tape easily fits around corners and curves.
To make yards and yards of continuous bias tape, lay out fabric and cut off one end at a 45-degree angle. Sew this cut piece to the other end. See Diagram #1.
On the reverse side of the fabric, mark off the desired bias tape width parallel to the 45 degree edge. (Diagram #1 shows five strips but mark as many as your fabric will allow.)
Place the two lengthwise edges right sides together and offset both ends the desired width of the finished tape. For example, for 1-1/4” tape, offset piece #1 and #5 (shown in Diagram #2) 1-1/4”. Sew a 1/4 ” seam along the length of the fabric creating a spiraled piece of fabric.
Cut along the marked lines in the spiral starting at the line between #1 and #2 and continue to the end.
To figure how much bias tape you will get out of a piece of fabric:
(1) Measure your piece of fabric that you are going to be cutting your bias strips from.
(2) Now multiply the measurement of the fabric by itself to get the squares inches of the area.
(3) Then divide the squares inches by the desired width of the bias strip.
For Example :
Square = 12”
So 12 x 12 = 144 square inches
Bias Tape Width = 2”
Therefore, 144 / 2 = 72 ” of 2" wide bias strips from a 12" square.