Bias tape, also known as bias binding, is a narrow strip of fabric that is cut on the bias, typically plain weave. The bias cut makes the resulting fabric strip stretchier than a strip cut on the grain, and it also has a better drape and conforms to curves better than fabric cut on the grain. Bias tape comes in different widths, ranging from extremely narrow (1/4 inch wide when flat) to extremely wide (as wide as 3 inches or more) . It is typically sold in meter or roll lengths by haberdashers.

Bias tape is used in making piping, binding seams, finishing raw edges, and is also used decoratively. It is often used on the edges of quilts, placemats, and bibs, around armhole and neckline edges instead of a facing, and as a simple strap or tie for casual bags or clothing. Bias tape can be used to decorate garments with bold accents, and bias-tape lines can detail an edge, fall within the body of a garment, and follow a curve.

There are two main types of bias tape: single-fold and double-fold. Single-fold bias tape has both vertical edges pressed underneath the strip, meaning that both vertical edges are on the fold. Double-fold bias tape is folded in half lengthwise, with one side slightly wider than the other. Double-fold bias tape is generally used to bind an edge and is visible from the outside of a garment, while single-fold bias tape is used as a narrow facing, which is turned to the garment’s wrong side.

Bias tape can be purchased pre-packaged or made at home using different fabrics. To make bias tape at home, a long strip of fabric is cut on the bias grain, folded and pressed so that the raw edges meet in the middle, and then folded in half lengthwise to make double-fold bias tape. Devices are available commercially to aid the home sewer in making folded bias tape, which folds the fabric and presses the folds into place.