Bias Tape Calculator
Calculate the fabric square needed to make continuous bias tape, or how many purchased packages to buy.
Measure all edges you need to bind
Common Bias Tape Uses
| Application | Common Tape Width | Type |
|---|---|---|
| Quilt binding | 2½" strips (makes 1¼" binding) | Double-fold |
| Garment neckline / armhole | 1" strip (½" finished) | Double-fold or single-fold |
| Appliqué outline | ½" strip | Single-fold |
| Bag / tote edge | 2" strip | Double-fold |
| Facing alternative | 1–2" strip | Single-fold |
| Piping casing | Varies by cord size | Bias-cut strip |
How to Use the Bias Tape Calculator
- Measure all the edges you need to bind and add them together for the total tape length needed (in inches).
- Select the strip width — for double-fold bias tape, the standard is 2" wide strips folded to 1" finished.
- Choose your joining seam allowance (¼" is standard for bias tape joins).
- Select a safety buffer to account for waste and errors.
- Click Calculate to see the fabric square size needed and how many purchased packages to buy.
How Continuous Bias Tape Works
- Cut a square of fabric. The size of the square determines how much tape you get.
- Cut the square in half diagonally to make two triangles.
- Sew the triangles together along the short straight edge (¼" seam) to make a parallelogram.
- Draw parallel lines across the fabric at the desired strip width.
- Join the top and bottom edges with a ¼" offset to make a tube. Sew together.
- Cut along the spiral lines to produce one continuous bias strip.
Formula Used
- The area of the fabric square (side²) divided by the strip width gives the theoretical tape length.
- A small amount is lost to seam allowances when joining; the calculator accounts for this.
- For a 20" square cut into 2" strips: 20" × 20" ÷ 2" = 200" of tape (theoretical).
Tips
- Cut strips on the true bias (45° to the grain) for maximum stretch and smooth curves.
- Pre-cut quilting strips are not bias — they are cut straight and do not stretch around curves.
- Use a bias tape maker tool to fold and press strips quickly and evenly.