Bias Tape Calculator
Calculate bias tape yardage from fabric square size, or find the fabric needed for a target tape length.
Supports 1/2 in, 3/4 in, and 1 in tape widths.
Bias tape is fabric cut at a 45-degree angle to the grain. Cutting on the bias gives the strip natural stretch, which lets it curve smoothly around necklines, armholes, and hems without puckering.
The formula for calculating how much bias tape you can get from a square of fabric is:
Total Length = Square Size² / Strip Width
What the variables mean:
- Square Size — the length of one side of your fabric square (in inches or cm)
- Strip Width — how wide you cut each bias strip. Common widths are 1 inch (2.5 cm) for single-fold and 2 inches (5 cm) for double-fold tape.
Number of strips is approximately the square size divided by the strip width.
Practical example (Imperial): A 36-inch fabric square cut into 2-inch strips yields 36² / 2 = 648 inches, which is 18 yards (16.5 m) of bias tape. That is enough to edge a full dress or a couple of quilts.
Practical example (Metric): A 90 cm fabric square cut into 5 cm strips yields 90² / 5 = 1,620 cm, which is 16.2 meters (about 17.7 yards).
Tips: Always add 10-15% extra length to account for seam allowances when joining strips together. When joining bias strips, sew them at a 45-degree angle for a flat, smooth seam. Press the tape in half with a bias tape maker tool for consistent folds. Lightweight cotton and cotton-lawn work best for bias tape because they fold crisply and hold their shape.