Sewing bias tape on curves requires pinning in short segments, easing the tape around the bend, and stitching slowly to prevent the tape from bunching or pulling the fabric out of shape

Bias tape follows curves because it is cut at a 45-degree angle to the grain, which gives it natural stretch. But that same stretch works against you if you do not control it. The tape will bunch on the inside of the curve and pull away on the outside unless you pin it down in small sections before you stitch, ease it gently as you go, and keep your presser foot pressure steady.

The method changes slightly depending on whether you are binding the edge of a curve (like the armhole of a garment) or explore tape to a curve that sits in the middle of fabric (like a decorative line). Both start the same way: pin short segments, stitch slowly, and press as you go.

Key Takeaways

  • Pin bias tape to a curve in 1- to 2-inch segments before you stitch, because curves shift and move as you sew.
  • Ease the tape gently around the bend by letting it bunch slightly on the underside while you keep the top flat and smooth.
  • Stitch at half your normal speed and keep even presser foot pressure so the tape does not slip or pucker.
  • Press the tape flat after every few inches of stitching to set the shape and catch puckering before it locks in.
  • For binding an edge curve, fold the tape in half lengthwise first, then pin and stitch in one pass rather than wrapping it around afterward.

Prepare the tape and mark your stitching line

Before you touch the needle, mark the exact line where the tape will sit. Use a fabric pencil, chalk, or a thin line of tailor's chalk to draw the curve on your fabric. If the curve is an edge (like an armhole), the line sits about 1/4 inch from the raw edge. If the curve is decorative and sits in the middle of the fabric, draw it where you want the tape to run.

Press your bias tape flat with an iron set to medium heat. If the tape is folded in half (which it usually is when you buy it), open it completely so you can see both long edges. This makes it easier to position and pin. If you are binding an edge, you can leave it folded for now and fold it again later, but for a decorative curve, work with it open.

Pin the tape in short segments, not end to end

This is the step that stops most puckering. Do not pin the entire curve at once. Instead, pin 1 to 2 inches at a time, starting at the point where the curve is least sharp. On an armhole, that is usually the shoulder seam. On a decorative curve, start at the flattest part.

Align one long edge of the tape with your marked line. Use a pin every 1 to 1.5 inches along that segment. Push the pin straight through the tape and fabric, perpendicular to the curve. As you move around the bend, the tape will want to shift. That is normal. Pin the next segment, then check that the previous segment still lies flat. Adjust if needed before you move forward.

On a tight curve (like a small armhole or a sharp turn), you may need to ease the tape by letting it bunch slightly on the underside. This is intentional. The bunching on the back allows the top to stay smooth and flat. If you try to keep both sides perfectly smooth, the tape will pucker in the middle of the stitch line.

Stitch slowly and keep pressure even

Set your machine to a straight stitch and reduce your speed to about half of what you normally sew. Use a presser foot that gives you good visibility — a 1/4-inch foot or an open-toe foot works well. Stitch along the inner edge of the tape (the edge closest to the center of the curve), removing pins as you reach them.

Keep your hands relaxed and let the feed dogs pull the fabric. Do not push or pull. If you push, the tape will bunch. If you pull, you will stretch it. Your job is to guide, not to force. Watch the tape ahead of the needle as you stitch. If it starts to shift, stop with the needle down, lift the presser foot, adjust the tape, lower the presser foot, and continue.

Stitch only the segment you pinned. Stop at the last pin of that section. Raise the presser foot, remove the pin, and stop. Do not continue to the next segment yet.

Press and pin the next segment before continuing

This is the second step that stops puckering. After you stitch each 1- to 2-inch segment, raise the presser foot and remove the needle from the fabric. Press that segment flat with your iron. This sets the shape and lets you see if any puckering happened underneath. If it did, you can pick out the stitches and restitch that section before moving forward.

Once the segment is pressed and flat, pin the next 1 to 2 inches of tape. Check that the previous segment still lies smooth. Stitch the new segment. Repeat this process all the way around the curve. It takes longer than stitching the whole thing at once, but you catch problems as they happen instead of discovering them after you have sewn the entire curve.

Wrap and stitch the second side for edge binding

If you are binding the edge of a curve (not a decorative line), you have one more step. After you stitch the first side of the tape to the fabric, fold the tape to the back side of the garment and pin it down. The fold of the tape should cover your stitching line by about 1/8 inch.

Pin this back side in the same short segments you used for the front. Stitch from the back, sewing as close as you can to the fold without catching the fold itself. This is called a stitch-in-the-ditch or edge stitch. Stitch slowly and press after each segment, just as you did on the front.

Some sewers prefer to fold the tape in half before they pin it to the edge, so they can stitch both sides in one pass. If you choose this method, fold the tape lengthwise so the two long edges meet, then pin it around the curve with the fold facing outward. Stitch down the middle of the tape. This works well on gentle curves but can be harder to control on tight ones.

Trim and finish the ends where they meet

When you reach the point where you started, you will have two tape ends that need to join. Stop stitching about 1 inch before you reach the starting point. Trim both ends of the tape so they overlap by about 1/2 inch. Open the fold of one end and tuck the other end inside it, so the raw edges are hidden. Pin this joint and stitch across it carefully.

If the joint sits on a curve, press it flat and check that it does not pucker. If it does, you may need to trim the overlap smaller or adjust how the ends meet. On a decorative curve, you can also overlap the ends on the top side and stitch across the overlap, which creates a small decorative detail.

Troubleshoot common curve problems

Puckering on the top side: This usually means you stitched too fast or pushed the fabric. Pick out the stitches in the puckered section, re-pin that segment, and stitch again at half speed. Do not push.

Tape pulling away from the curve: The tape is stretched too tight. Pick out the stitches, ease the tape more generously around the bend, and re-pin before stitching. On a very tight curve, you may need to trim a tiny wedge from the seam allowance to reduce bulk.

Bunching on the back side: This is normal on tight curves and is actually what you want. If the bunching is severe, you may have eased too much. Re-pin with less ease and try again. If the bunching is moderate and the front is smooth, leave it — it will not show when the garment is worn.

Tape twisting as you sew: You are not pinning enough segments. Pin more frequently — every 1 inch instead of every 1.5 inches — and check the tape before you stitch each segment.

Frequently Asked Questions

Can I use regular tape instead of bias tape on a curve?

No. Regular tape is cut parallel to the grain and has no stretch. It will wrinkle and bunch on a curve because it cannot bend. Bias tape is cut at 45 degrees to the grain, which gives it the stretch it needs to follow a curve smoothly.

What if my curve is very tight, like a small armhole?

Pin in 1-inch segments instead of 2 inches, and ease the tape more generously on the back side. You may also need to trim a small wedge from the seam allowance (the fabric between the curve and the raw edge) to reduce bulk. Cut a small triangle from the seam allowance every 1/2 inch or so, being careful not to cut into the stitching line.

Do I have to press after every segment?

You do not have to, but it is the fastest way to catch puckering before it sets. If you skip pressing, you risk stitching puckers into place and having to pick them out later. Pressing takes 30 seconds per segment and saves you time overall.

What presser foot should I use?

A 1/4-inch foot or an open-toe foot gives you the best view of the tape and curve. Some sewers use a walking foot to help feed the tape evenly, but on a curve, a regular foot with even pressure works just as well. Avoid a wide foot that blocks your view.

Can I machine-stitch both sides of the tape in one pass on a curve?

Yes, if you fold the tape in half lengthwise before pinning and stitch down the middle. This works well on gentle curves but is harder to control on tight ones. If you try it and the tape puckers, go back to stitching one side at a time.