How to finish a neckline with bias tape
Blogpost | Tutorials

How To Sew a Bias Tape Neckline

In this tutorial I’ll show you how to finish a neckline with bias tape. We’ll be walking through Step 2 of the Onyx Shirt instructions, but you can follow these steps for any curved seam finished with bias tape. Before I used the techniques shown here, it took me quite a few tries to get this right. I always felt like tutorials made it seem so easy. And yet I could not get the neckline to lay flat, there were wrinkles, just not something I could really be proud of. But I’ve developed/discovered a few tricks that now give me the results I want, and I hope that after this tutorial you can be proud of your bias tape necklines too!

Bias tape or binding can be used as a finishing method to enclose the raw edge of a neckline. The key to sewing a bias tape neckline is using the right kind of bias tape, pressing after each step, understitching, and shaping the bias tape to the neckline curve with your fingers.

How to finish a neckline with bias tape

Before you start

Lets start with a few general tips. First you should consider the kind of fabric your tape is made of in relation to your top. Store bought bias tape can be quite stiff. This is no problem when you’re using a medium weight fabric. When you’re using lightweight fabrics it’s easier to either use a lightweight bias tape or to make your own bias tape. If you make bias tape from the same fabric you’re using for your top you get the best results. A great tutorial for making your own bias tape is this one from Colette.

I made my own tape for the Onyx product samples. For this tutorial I made it difficult for myself and used a medium weight tape for a lightweight fabric. Just to show you that even then you can get a flat, wrinkle free neckline!

Second, in the Onyx instructions we recommend using 3/8″ (1 cm) single fold bias tape. The narrower the bias tape, the easier it is to get a flat neckline. If you only have double fold bias tape, just cut a strip off so you get the required width. That’s what I did for this tutorial, too.

How to finish a neckline with bias tape

What you need

  • Your Onyx shirt, sewn up to Step 2
  • 75-80 cm of bias tape, depending on the neckline
  • sewing machine
  • iron
  • scissors

Step 1: First seam

How to finish a neckline with bias tape

Open up one side of the bias tape and press it flat. Position the tape on the right side of the fabric, at the center back of the neckline (indicated by the pen mark), so that the crease of the opened side is a 3/8″ (1 cm) from the raw edge. Pin the tape 1″ toward the shoulder seam. Leave a tail of 1″ past the center back.

How to finish a neckline with bias tape
How to finish a neckline with bias tape

Start sewing in the crease of the tape 1″ from the center back. Sew around the neckline until 1″ from the center back. I find it easiest not to pin the tape in advance, but to position it as I sew. Be careful not to stretch the fabric, let the tape follow the curve of the neckline.

How to finish a neckline with bias tape

Bring the two tails together at the center back. To find the place where they should meet, fold one double. Fold the other one against it in the opposite direction. Then match and sew the folds together.

Open up the tails and press. Trim the excess tape. Sew the remaining 2″ of tape to the back neckline.

Step 2: Understitching

Understitching is a line of straight stitching sewn just beyond the seam line of two pieces that have been sewn together. One of the pieces is the seam allowance of your garment (in this case the fabric), the other is what will be on the inside (the bias tape). In order to keep the neckline edge sharp and clean, you understitch the bias tape to the seam allowance so it won’t roll to the outside.

How to finish a neckline with bias tape
How to finish a neckline with bias tape

Press the bias tape up, away from the bodice. You don’t need to press the tape flat – just press the edge of the tape with the tip of your iron. Stitch through the tape and the seam allowance of the bodice, as close to the pressed edge as you can. Trim the seam allowance of the garment close to the understitching.

Turn the shirt inside out and fold the bias tape out along the neckline curve. Press the bias tape along the curve, so no tape is visible on the right side of the garment. The under stitching ensures that the edges roll nicely to the outside, so the tape isn’t visible from the right side.

Step 3: Shaping

What you’ve done by attaching the bias tape, is sewn a straight piece of fabric (the tape) to a curved one (the neckline). No wonder it doesn’t lay flat nicely, right? So what we’ll do next is shape the tape into a curve. This is what makes the difference between a flat bias neckline and one that stands away from the body.

By stretching the outer edge of the bias tape you shape it to match the neckline curves. In the images above you can see the difference this makes. The video below shows how I shape the bias tape.

You hold the tape between your fingers, and move your palms toward each other. This stretches the outer edge but not the seam. You can do this lightly at the straight parts like the back neckline, and stretch it more at curved parts, like the shoulders and the curved front of the neckline.

Step 4: final seam

How to finish a neckline with bias tape

Give the neckline a good press. Sew the tape to the neckline. Keep the fabric underneath taut to prevent wrinkles. Follow the curve of the neckline.

How to finish a neckline with bias tape
How to finish a neckline with bias tape

Give the neckline a final press. This one eliminates the last wrinkles, as shown by the difference in the images above. The second one has only some slight wrinkling and lies flat against the body.

It’s a bit of a fiddly process and even with the best tutorial it requires some practice. The Love To Sew podcast has a fun episode all about bias tape if you’d like to know more. If you have any questions, leave a comment below.

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29 Comments

  1. Thanks so much! I can’t wait to try this – I’ve never managed to sew a neckline that lies flat. KR nina.

  2. That is such a great tutorial – now I know why my bias binding doesn’t sit flat – thanks!

  3. Hi. I’m currently making a shirt that has bias tape on the inside of the sleeve like yours does. However, once I have it sewn I can’t get those wrinkles out. I’ve done it multiple times and I am still having trouble ironing them out. Any ideas? Thank you! This was an excellent tutorial as well!

    1. Hi Holly, you mean the wrinkles on the right side of the fabric? That means the bias tape is less curved than the fabric, so it pulls it together. Try to shape the bias tape into a sharper curve as shown in the video. Ironing the curve in also helps.

  4. I’m thinking of all kinds of lazy ways to finish the neck, but I this… I never thought to understitch. I think that’s the secret that makes it cleaner. Thanks.

  5. Hi, I have a question… after the Understitching step, but before the Shaping step, do you press the bias tape to the inside of the garment? It looks like it from the photo but I cant find it in the directions. Thanks so much! I am trying to figure out how to do this!

    1. You’re absolutely right, thanks for noticing! So yes, press it to the inside after understitching.

  6. Wow here I am using this tutorial 2 years after you wrote it. I have taken courses on bias application and purchased every book. I just completed utilizing your instructions on a white linen blouse and I am so happy. Now I just need to perfect the actual making of the bias tape. Thank you for sharing your wisdom.

  7. Help . My McCalls instructions say to use quarter inch bias tape and there’s no mention of trimming. Also looks like they want me to stitch first on the right side of fabric, (shaded) and then final stitching after basting is from the inside! I think it would be sloppier. Also says to sew the two pieces, tape and blouse together right at the raw edges, not 3/8 inch down. This is an important project, due now! If I sew 3/8 down will it alter the size of the neckline??? Thank you

    1. Hi Sigrid. First, yes sewing 3/8 down will make the neckline larger, so follow Mccalls there. These instructions are more about the sequence of steps that you can take. I don’t quite understand how the order of steps is different in your instructions. The most important thing in this tutorial is the shaping of the tape with your fingers.

  8. Hi Lisa. I have been looking at tutorial after tutorial and for some reason yours just clicked with my brain. I am relatively new to sewing and have avoided making shirts because of the neckline. I am about to finish my newest shirt and this has helped me out a great deal ? Thank you so much!

  9. Hi wish I’d been taught this 40 odd years ago in school!!! Thank you I will never do it the old way again

    1. Best compliment :) I really don’t know why I haven’t seen this before, it makes so much sense to me.

  10. Lisa, This is the best bias binding/neckline tutorial ever! I’ve been sewing – on and off – for about fifty years and I’m happier with the end results after following your instructions and photos/video than I’ve ever been with any of my previous attempts. Thank you!

  11. Thank you! My neckline will look much better. However, the next time, I will make my own bias tape and use the double fold bias tape method. It’s much faster.

    1. It certainly is. I do find it trickier to make sure I sew through the bottom layer as well, and it doesn’t look as neat. But it’s definitely faster :)

  12. Hi, this tutorial appears to show bias facing. Do you have similar one for bias binding? Thanks! This was very helpful.

    1. Hi, do you mean with bias tape on the outside or when you sandwich the fabric between the tape? I don’t have those tutorials, but the crucial step – shaping the tape – works for those methods too.

  13. I’m a new sewer, took me 69 years to get interested in it, now I can’t learn fast enough. But I do have a few questions about your tutorial… are you starting on the right side or wrong side of the fabric? It LOOKS like the right side to me, but like I said, I’m just learning and I’m not sure. Second, step 2, understitching… I’m not sure where or what you’re stitching. I THINK I’m suppose to understitch on the tape, but not through the fabric… do you fold the fabric out of the way to sew this? I’ve never understitched before. And lastly… you can’t see the tape on your finished top! I thought the tape folded OVER the raw edges so that half was on the front of the top, the other half is on the inside. But NO tape shows on your top! I’m so confused!

    1. Hi Charlene, excellent questions! I’m starting on the right side of the fabric, so in the end the bias tape is on the inside of the garment. However, if you want it to be visible, just start on the wrong side of the fabric! The understitching is done through the bias tape AND the fabric. Last, folding the tape over the raw edge is a different method, one that you would use in binding a quilt for instance. It can also be done for garments, but the seam allowance has to be drafted especially for this. The Onyx neckline has a seam allowance, if you would just fold over the tape, the neckline would end up higher than intended.

  14. Thanks for the tip & video of stretching the edge with your hands. I just wasn’t getting enough of a stretch on the outer edge until I used my fingers just on the edge like you demonstrated!! Maybe one more practice run and I’m ready for my garment. This crossover apron takes a lot of bias tape.

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