Continuous Bias Binding Calculator
Continuous bias feels almost like a sewing magic trick: one fabric square becomes a long, flexible strip that curves smoothly around an edge. This calculator tells you how large that starting square needs to be.
Enter the edge length and strip width and you get a safe square size, expected yield and a simple visual reminder of the diagonal method. No trial-and-error sizing, and no discovering halfway around a neckline that the strip is too short.
The recommended square is enlarged until its estimated yield, after join losses, is at least the binding required.
A clear result in five steps
- 1Measure the complete edge.
- 2Enter the cut width of the bias strip.
- 3Choose safety and join-loss allowances.
- 4Cut the calculated square diagonally.
- 5Offset, join, mark and cut the continuous spiral.
The maths, without the mystery
The initial square comes from required length × strip width. It is then enlarged until estimated yield after N−1 join losses is at least the required bias length.
Frequently asked questions
Why is the square larger than the simple area formula?
The corrected result also covers estimated losses at joins.
Is the yield exact?
It is conservative planning; construction and trimming can vary.
Should I test the method?
Yes—practise on inexpensive fabric before cutting a valuable print.