Bias Tape Width & Length

About This Tool

Why Bias Tape Width & Length Math Matters

The Formula

Square side —

the measurement in inches of one edge of the fabric square you cut

Finished width —

the folded width of the tape as it will sit on the garment

Bias length —

the total continuous strip in inches the square can yield

The result is divided by 36 to show yards, and the estimate assumes a normal 45 degree cut with the strips joined end to end.

Worked Example: Step by Step

1. 1You need bias binding for a scalloped neckline and decide on a half inch finished tape.
2. 2You cut a 22 inch square from lightweight cotton and enter that side length.
3. 3You type the finished width as 1 inch to keep the estimate conservative.
4. 4The calculator squares 22 to 484 and subtracts the width allowance from the top.
5. 5It divides by eight times the width and returns about 60 inches of usable strip.
6. 6That reads out as 1 yard and 24 inches, which comfortably wraps the neckline twice.
7. 7You now know one square is enough, and you keep the second square in reserve only for mistakes.
8. 8Checking the yield on paper first turns a binding that used to run out into a single calm, measured cut.

How to Use This Calculator

1. Decide the finished tape width you want on the garment.
2. Choose the square size you plan to cut, or enter one you already have.
3. Type both numbers in inches into the calculator.
4. Read the total strip length in inches and yards.
5. If it falls short of your edge, size the square up or the tape down.
6. Cut corner to corner, offset and join the strips for one continuous run.

Key Terms

Bias

fabric cut at 45 degrees to the selvedge so the strip stretches and eases around curves

Continuous bias

a method that joins strips from one square into a single long binding with no loose ends

Finished width

the width of the folded tape as it appears stitched onto the project

Double fold

tape folded twice so the raw edges are hidden inside the bind

Yield

the total length of strip a given square can produce at a chosen width

Selvedge

the self-finished factory edge of the fabric that runs parallel to the lengthwise grain

Miter

the folded 45 degree corner turned at each square edge so the binding lies flat and sharp

Bias Tape Width & Length Reference Table

These are planning estimates for a plain straight-grain square, so add a little spare for the joins and for any fabric whose true bias stretch differs from the ideal.

Common Mistakes & Pro Tips

• Cutting the square from straight grain instead of true bias, so it refuses to ease around the curve.
• Sizing the square off the finished width while forgetting the doubled fold uses more fabric than it looks.
• Assuming a larger tape width costs nothing, when wider binding slashes the yield from the same square.
• Not accounting for the joins, which trim several inches off the theoretical length of every run.
• Measuring only the flat edge and ignoring the corners that eat extra binding on a curved hem.
• Joining strips at a point on the curve instead of a straight section, leaving a lump where it shows.
• Pressing the fold unevenly before stitching, so part of the bind sits thick and refuses to lie flat on the inside.

Real-World Use Cases

• Binding the curved edge of a flannel quilt.
• Finishing a scalloped or V-neckline on a blouse.
• Facing the hem of a circular or bias-edge skirt.
• Wrapping a curved placemat or runner edge.
• Making matching tape for a batch of drawstring bags.
• Judging whether a stash square covers a binding before shopping.
• Sizing continuous bias for a long quilt so one run wraps all four sides.
• Cutting matching tape to bind a set of round coasters or mats.

Bias Tape Width & Length: Frequently Asked Questions