The basic method: pin, stitch, fold, and press as you go

Sewing bias tape around a curve works the same way as sewing it on a straight edge, except you stop every few inches to ease the tape around the bend. The tape itself is already cut on the bias, so it will stretch—your job is to control that stretch so it lies flat instead of bunching or pulling.

Start by pinning the bias tape to the wrong side of your fabric, just as you would on a straight seam. Pin every 2 to 3 inches along the curve, pulling the tape gently as you pin so it follows the fabric's edge without slack. The curve will want to create extra fabric on the inside of the bend; pinning prevents that from becoming a pucker later.

Sew with a straight stitch, using the crease in the bias tape as your guide. Sew slowly around the curve—speed causes the presser foot to push fabric unevenly. Stop with the needle down every inch or so, lift the presser foot, adjust the tape and fabric so the next inch lies flat, then lower the foot and continue. This pause-and-adjust rhythm is what keeps curves smooth.

Key Takeaways

  • Pin bias tape every 2 to 3 inches around the curve, pulling gently so the tape follows the edge without slack.
  • Sew slowly and stop every inch to lift the presser foot, adjust the fabric, and check that the tape lies flat before continuing.
  • Trim the seam allowance to 1/8 inch after stitching, especially on tight curves where bulk causes puckering.
  • Press the tape to the back side while it is still warm from sewing, using the tip of the iron to crease it into the curve.
  • On very tight curves like armholes, clip into the seam allowance between stitches so the fabric can spread without pulling the tape.

Trim the seam allowance before folding the tape to the back

After you stitch the first side of the bias tape, trim the seam allowance down to 1/8 inch. Use small scissors or a rotary cutter and ruler. On a curve, this step matters more than on a straight seam because bulk in the seam allowance will push the tape away from the fabric and create a visible ridge on the finished side.

Trim close to the stitching line, but do not cut into the stitches themselves. If your curve is very tight—like an armhole or neckline—clip into the seam allowance at an angle every 1/2 inch, stopping just short of the stitching. These clips let the fabric spread slightly so it does not pull the bias tape tight and cause it to pucker on the finished side.

Press and fold the tape while it is still warm

Fold the bias tape to the back side of the fabric while the seam is still warm from sewing. The warmth makes the tape more pliable and helps it settle into the curve without fighting you. Use the tip of your iron to crease the fold line as you go, working in 2 to 3 inch sections.

Press the tape flat against the back of the fabric, using the iron tip to push it into any curves or hollows. Let each section cool before you move to the next one. If you rush and fold cold tape, it will spring back out of shape and you will have to re-press it later.

Stitch the back side of the tape by hand or machine

Once the tape is folded and pressed to the back, you have two options: stitch it by hand with a ladder stitch or whip stitch, or use a machine stitch. Hand stitching gives you more control on curves and is less likely to create puckers, but it takes longer. Machine stitching is faster if you sew slowly and stop frequently to adjust.

If you machine stitch, use a straight stitch and sew from the back side, stitching just inside the fold of the bias tape. Sew slowly and stop every inch to lift the presser foot and check that the tape is still lying flat. If you hand stitch, use a ladder stitch or whip stitch and a thread that matches the tape, taking small stitches (1/8 inch or smaller) so the thread does not show on the front.

Handle very tight curves by stretching the tape slightly as you sew

On very tight curves like armholes, necklines, or the inside of a collar, the tape may still want to bunch even after you trim and clip. The solution is to stretch the tape slightly as you sew the first side. This sounds counterintuitive, but a small amount of tension prevents the tape from folding back on itself when you fold it to the back side.

Stretch the tape by pulling it gently forward as you feed it under the presser foot. Do not pull so hard that you distort the tape or the fabric—just enough tension so the tape lies smooth and the fabric does not bunch ahead of the needle. This takes practice; test on a scrap of fabric first if you are new to this technique.

Common mistakes and how to fix them

Puckering on the finished side: This usually means the seam allowance was too thick or the tape was not pressed flat while warm. Rip out the back stitching, trim the seam allowance thinner, re-press the tape, and stitch again. If the curve is very tight, clip into the seam allowance as described above.

The tape pulls away from the edge: You did not pin tightly enough or you did not ease the tape around the curve as you sewed. Rip out the stitching, re-pin every 1 to 2 inches (closer than before), and sew again, stopping more frequently to adjust. On the next project, pin more densely from the start.

The tape twists or folds unevenly on the back: The tape was pressed cold or not pressed at all. Rip out the back stitching, re-press the tape with a warm iron, and stitch again. Pressing is not optional on curves; it is what makes the tape stay in place.

Visible stitches on the front: Your back stitching is too close to the edge of the tape or your thread is too dark. Use a thread that matches the tape and stitch just inside the fold of the tape, not at the very edge. If the damage is visible, you may need to rip and re-stitch.

Frequently Asked Questions

Do I need to pre-shrink bias tape before sewing it on a curve?

No. Bias tape is usually pre-shrunk at the factory. If you are using vintage tape or tape from an unknown source, a quick test is to wet a small corner and let it dry—if it shrinks noticeably, wash the whole roll in warm water and dry it flat before using. Most modern tape does not need this step.

Can I use a bias tape maker to make my own tape for curves?

Yes, homemade bias tape works the same way as store-bought. The advantage is that you can cut it wider or narrower to suit your project. The disadvantage is that homemade tape is less stable and may stretch unevenly on tight curves. If you make your own, cut it on the true bias (45 degrees to the grain) and press it carefully before sewing.

What is the difference between single-fold and double-fold bias tape on curves?

Single-fold tape has one fold and is used when you want to fold it yourself as you sew. Double-fold tape comes already folded in half and is faster to use, but it is stiffer and harder to ease around very tight curves. For armholes and necklines, single-fold tape gives you more control. For gentler curves, double-fold works fine.

How do I sew bias tape around an inside corner or point?

At an inside corner, stop stitching just before the corner, clip into the seam allowance at an angle right at the corner, then continue stitching. The clip lets the fabric spread so the tape does not pull. When you fold the tape to the back, the clip will open slightly and the tape will lie flat. Press carefully around the corner to make sure the fold is sharp.

Why does my bias tape bubble up on the finished side even after I pressed it?

Bubbling usually means the seam allowance is still too thick or the tape was not stretched enough as you sewed the first side. Rip out the back stitching, trim the seam allowance to 1/8 inch or thinner, and re-press. If the curve is tight, clip into the seam allowance. On the next project, stretch the tape slightly as you sew the first side to prevent this.