Bias Binding — Theoretical Minimum Square
See the area-based square that contains the binding length you need. It is not a guaranteed cut yield.
Calculator
Calculated in your browser. These measurements are not sent to the server.
This is a theoretical minimum square. It is not an exact continuous-bias yield. Use the straight-grain binding calculator for a strip count and purchase length.
Result
- Theoretical side
- 11.726 in (29.784 cm)
- Square rounded up to the next inch
- 12 in (30.48 cm)
- Area used for the estimate
- 137.5 sq in
This is an area-based theoretical minimum square. It is not a guaranteed cutting yield. Tube seams, trimming, the start and end of a spiral, and squaring can use extra fabric. An exact continuous-bias calculator is not published.
The square side is the square root of required length times cut strip width.
That side is rounded up to the next whole inch so the displayed size does not change when you switch units.
No continuous-bias tube, offset, or spiral loss is modeled.
How this calculation works
The area is required length times cut strip width. The theoretical side is the square root of that area.
The side is rounded up to the next whole inch so the physical square stays the same when you switch units.
Real continuous bias also loses fabric to the tube seam, trimming, and the start and end of the spiral. Those losses are not included.
Worked example
55 in of 2.5 in strip
Area = 137.5 square inches. The square root is about 11.73 in.
Rounded up, the theoretical square is 12 in.
A longer example, 320 in by 2.5 in, has a square root of about 28.28 in and rounds up to 29 in. Neither result promises that the sewn strip will come out that long.
Assumptions and limitations
- Bias direction is 45 degrees. The construction method itself is not simulated.
- Rounding is to the next whole inch, then displayed in the unit you selected.
- An exact continuous-bias calculator is not published.
- Do not buy only this square and expect the full strip length after sewing.
Common questions
Can I use this square as the fabric to buy?
Only as a lower-bound sketch. Tube seams, trimming, and the ends of the spiral can consume more fabric than the area formula shows.
Where is straight-grain binding?
Use the quilt binding calculator. That tool is the launch-ready strip and yardage calculation.