Bias Binding Calculator — Fabric for Continuous Bias Strips

Bias binding is a strip of fabric cut at 45 degrees to the grain. It stretches around curves smoothly, making it ideal for finishing necklines, armholes, quilt edges and curved seams. It can be single-fold or double-fold.

For single-fold binding, cut strips twice (×2) the finished width. For double-fold binding, cut strips four times (×4) the finished width, plus a few millimetres for the turn of the cloth. For example, a 12mm finished double-fold tape is cut from roughly 5cm (2 inch) strips. Common finished widths are 6mm, 10mm and 12mm. This calculator works it out for you.

Instead of cutting individual diagonal strips and joining them, you cut a square of fabric, mark lines, join two edges with an offset, then cut in a spiral to get one long continuous strip. It is faster and produces less waste.

Always make 10-15% more binding than you need. You lose a small amount at the start and end, plus you need overlap for joining. For quilt binding, add 25cm to the quilt perimeter.