About this tool
Bias Tape / Continuous Bias Calculator finds the size of fabric square you need to make a length of continuous bias binding — the stretchy, diagonal-grain strip used to finish curves and necklines. Enter the finished bias length you want and the strip width you cut, and it returns the fabric square to start from, the fabric area used and the length in yards.
The area of fabric consumed equals the bias length × strip width, because a continuous-bias square is sliced into one long strip of that width. The square's side is therefore ceil(√(length × strip width)), rounded up to a whole inch. Enter a square you already have and the tool reverses the math, reporting the yield = side² ÷ strip width in inches of bias.
Cutting on the bias — 45° to the grain — lets the tape stretch smoothly around curves, unlike straight-grain binding. The continuous-bias method turns a single square into one long strip with far fewer joins than cutting separate diagonal strips, wasting very little fabric.
Frequently asked questions
Why cut binding on the bias?
Bias-cut strips stretch and ease around curves — armholes, necklines, scalloped edges — without puckering, which straight-grain binding cannot do. The trade-off is that the diagonal cut uses a little more fabric.
How does the continuous-bias method work?
You mark a square, cut it corner-to-corner, offset the halves and seam them into a parallelogram, then draw strip lines and sew it into a tube. Cutting along the marked line spirals the fabric into one long continuous strip with minimal waste.
What size square do I need?
Since the strip's area equals length × width, the square's side is the square root of that area, rounded up to a whole inch. The tool does this for you and can also tell you how much bias a square you already own will yield.
Can I use this for quilt binding?
Yes, when you want bias binding on a quilt — helpful for rounded corners or to show off a stripe or plaid on the diagonal. For ordinary straight-grain quilt binding, the quilt-binding calculator is the quicker route.
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