Tools you might need next
Calculate how many yards of fabric you need for a sewing project. Plan pattern layout, width, and repeats to buy the right amount of material.
Calculate quilt backing fabric needed including overhang and seam allowance. Size backing for longarm, domestic machine, or hand quilting projects.
Calculate seam allowance adjustments for pattern alterations and garment fitting. Add or subtract ease when resizing or modifying sewing patterns.
From a square with side S and strip width W, approximate total bias length equals the square area divided by strip width, minus seam losses.
Bias length ≈ (S² / W) × 0.97 (adjust for seam joins)Mark parallel lines on the marked bias tube and offset one side by one strip width before sewing and cutting the spiral.
Number of strips ≈ S / W (before continuous join method)Bias stretches around curves; straight grain uses less fabric on square quilts. Bias requires ~30% more fabric for same perimeter on curved projects.
Perimeter binding = 2 × (width + length) + 12 in easeUpdated: July 2026
Yields roughly 150+ inches continuous bias before joins — enough for a large throw quilt binding with mitered corners.
Curved edges require true bias; calculate from square method because cross-grain strips pucker on curves.
Narrow 1.5-inch strips from a fat quarter square cover armholes on two garments — verify length against armhole circumference plus overlap.
Cross-grain has minimal stretch — use true bias for curves, scallops, and armholes to avoid rippling.
Add 12+ inches to perimeter for mitered corners and final overlap seam when comparing to calculated bias length.
Continuous bias binding is cut from a fabric square on the true bias for stretch around curves. Enter square size and desired strip width to calculate total bias length, number of seams, and equivalent yardage for quilt edges and garment finishing.