Methodology
Formula version 2026.09.1. Geometry is calculated in inches after an exact unit conversion.
One inch is 2.54 centimeters. One yard is 0.9144 meters. Those factors are not rounded during a calculation.
Display text may show a shortened number. Purchase quantities round up to an increment you can change. The suggested starts are 1/8 yard and 0.1 meter. A result is never rounded to the nearest increment.
Suggested values such as 4 inches of backing overage, 12 inches of binding extra, 2× curtain fullness, and 42 or 54 inch usable widths are editable starting points. They are not described as the required industry amount.
Invalid input is rejected. A negative length is not silently turned into a positive one.
Not treated as exact
- Circle-skirt yardage. The tool reports radii and a fabric-width warning.
- Continuous bias yield. Only a theoretical minimum square is shown.
- Mitered quilt borders.
- Half-drop repeats, plaid matching, and motif centering.
- Zipper plaques, piping, welt, and foam compression on cushions.
- Lining and interlining on curtains.