A bias tape is a long, thin piece of fabric that is cut on the bias of the fabric. You can use it to hem your projects or to create a decorative edge. The biggest advantage of bias tape is that it fits naturally along curved edges, making them look neat. While you can definitely purchase pre-made bias, you can also make your own bias tape at home. This allows you to match the fabric that you're using exactly.
Cut a length of fabric "on the bias." This means at a 45-degree angle. You want the strip to be twice as wide as your desired finished product if you are making single bias tape, and four times as wide if you're making double bias tape.
Square the edges of the fabric strips. The strips that you cut will have pointed edges because you cut them at a 45 degree angle rather than straight on. Cut this small point off.
Sew several strips together if you need a long piece of bias tape. Do this by putting two strips together at a right angle and then sewing on a diagonal from one corner to the other. Trim the excess seam and iron flat.
Fold the long strip in half and use your iron to press it. When you've finished the whole strip, open it up again.
Press the two cut edges into the center line. This creates single bias tape.
Fold on the center line again and press. This creates a double bias tape.