What is bias binding?

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.

What width should I cut bias strips?

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.

What is the continuous bias method?

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.

How much extra should I make?

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.

SewCalcs

Bias Binding Calculator — Fabric for Continuous Bias Strips

Calculate the fabric square size needed to make continuous bias binding strips.

Binding Length Needed

Total length of bias binding required

Strip Width

Width of the cut bias strips (or set to 0 to auto-calculate)

Fold TypeDouble fold is more common and gives a neater finish

Finished Width

Desired finished binding width when sewn on

Price Per Metre (optional)

Fabric price per metre for cost estimate

How We Calculate This

The continuous bias method uses a square of fabric. The total area of the binding strips must equal the area of the fabric square.

The formula

Total strip area = Binding length x Strip width

Square side = sqrt(Total strip area)

Strip width from finished width

Single fold: Finished width × 2 (+ a few mm for the fold)

Double fold: Finished width × 4 (+ a few mm for the fold)

e.g. a 12mm finished double-fold tape is cut from ≈5cm strips.

Frequently Asked Questions

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Last updated: March 2026

All calculations are estimates. Always verify quantities before cutting or purchasing fabric.