Tutorial: How to perfectly fit bias tape to an armhole or neckline

bias tape finished top

Inside (left) and outside of top finished with bias tape facing.

During the construction of my Sorbetto top I suddenly realised how I can guarantee that bias tape will fit perfectly in any armhole or neckline (or any other place where the beginning and end of bias tape meets such as bag tops, hems and quilts). Until now I was somewhat mystified by how to do this properly and usually managed to fit it by a process of trial and error. Not anymore! It turned out to be very easy and since I am guessing that I am not the only one who could do with some clarification on this topic I thought I’d share my newfound knowledge in my first tutorial.

I prefer to match up two ends of bias tape with a seam that is at a 45 degree angle with the length of the tape instead of a 90 degree angle.  A huge advantage of having a seam that is at a 45 degree angle is that it will create much less bulk when the tape is attached to the project, especially when the bias tape is used to encase a fabric edge. I also think that a 45 degree angle seam will be more stable because this seam will run parallel to the grain line of the fabric since the fabric from which bias tape is made is cut on the bias.

The problem though with the 45 degree angle is where exactly to sew this seam to ensure that the tape will fit your opening perfectly and this is what I am now able to explain to you. I figured it out while trying to apply a method for attaching a binding to a quilt to the neckline of the Sorbetto and failing miserably. The bias tape turned out much too long. Then in a true light bulb moment I realised that for the quilt binding I had to add 5 cm (2’’) to the length of the binding at a certain point because the unfolded binding strip was 5 cm wide. The fabric strip I used to make my own bias tape for the neckline was only 2.5 cm (1’’) wide so that is why I ended up with a much too long strip to fit my neckline. When I added 2.5 cm instead of 5 cm my bias tape suddenly fit perfectly!

How to match up two ends of bias tape to sew the 45 degree angle seam.

I made another Sorbetto to demonstrate two methods for creating perfectly fitting bias tape. In sewing there are usually several ways to the same end result and it’s up to you to figure out which method works best for you. For the top in this tutorial I used bias tape to create a facing on the inside of the garment, but these methods can also be used to create an outside facing or for encasing a fabric edge in bias tape (which I think is what bias tape is used for most often). Please note that this tutorial is only to be used with woven fabrics. When attaching stretch bias tape to knit fabrics other rules apply.

Method 1: “Leave a gap”

Step 1.1: Make your own bias tape or get a piece of store bought tape that is a little longer than the opening you want to attach it to. If this is the first time you are attaching bias tape to an opening I suggest that you make it at least 10 cm (4’’) longer.

Step 1.2: Pin the bias tape to the opening, leaving the ends of the tape trailing off. I try to make sure that the place where the seam will end up is in a spot where it is hardly noticeable, such as under the arm when attaching the tape to an armhole or near the shoulder seam when attaching it to a neckline. I wouldn’t match it up exactly with another seam though as this will create unnecessary bulk.

Step 1.3: Stitch the bias tape to the opening leaving approximately a 10 cm/4’’ gap between the start and finish of your stitch line. Backstitch a couple of stitches at the beginning and end to secure.

Step 1.2 and 1.3.

Step 1.4: Cut off the left end of the bias tape so that the end stops in the centre of the gap. This is not something that you need to measure accurately but your cut should be straight.

Step 1.4

Step 1.5: Align the right end of the bias tape with the gap. It might be helpful to use some pins to secure the tape if the opening is very curvy.

Step 1.6: Fold the left end of the bias tape over the right end. Mark on the right end of the tape where the left end stops. This is something that you do want to do accurately.

step 1.6

Step 1.7: Now it is time to add enough length to the right end of the bias tape to be able to sew the 45 degree angle seem. The amount that needs to be added is the unfolded width of the bias tape. In my case this is 2.5 cm (1’’). Use a ruler (or a piece of the unfolded bias tape) to measure this distance on the bias tape. Draw a line across the bias tape to indicate where this measurement stops.

Step 1.7

Step 1.8: Cut off the right end of the bias tape on the second marking that you made.

Step 1.8

Step 1.9: Match up the edges of the bias tape as indicated in the picture and sew the two ends together as shown. It can be helpful to draw the line that you want to stitch with chalk or disappearing marker so you can sew on the line. After sewing the seam check whether you didn’t accidently twist the bias tape. Press the seam open and trim the seam allowances.

sew bias tape together

Step 1.9

Step 1.10: Pin the bias tape to the gap and stitch in place.

Step 1.11: Fold the tape over to the other side and edge stitch in place.


Step 1.10 and 1.11

You are done and should now have a lovely looking bias tape bound opening!

Bias tape finished armhole!

Method 2: “Create a circle”

Step 2. 1: Carefully measure your armhole or neckline and write down the measurement. This step is very important, if you do not do this accurately you run the risk that your bias tape will not fit as perfectly as you hoped it would! For the top that I used for this tutorial the neckline measured 75 cm.

Step 2.2: To the measurement from step 1 add the width of your unfolded fabric strip or store bought bias tape. Write down this measurement as well. I my example I used 12 mm (1/2’’) bias tape, which was made from a 2.5 cm (1 inch) wide strip. So I added 2.5 cm to my measurement from step 1, which was 75 cm and ended up with a total of 77.5 cm.

Step 2.3: Make your own bias tape or use store bought tape. Cut it exactly to the measurement that you wrote down in step 2. Do, however, slightly stretch the bias tape when you measure it. It has some stretch due to being cut on the bias and if you don’t stretch it out just a little bit, it might end up too long when you fit it into the opening.

Step 2.4: Now it is time to create a circle with your bias tape. Match up the edges of the tape as shown in the picture and sew the two pieces together as indicated. Check whether you didn’t accidently twist the tape and ended up with a Möbius strip, which will be impossible to attach to the opening (this, of course, totally didn’t happen to me…).  Press the seam open and trim the seam allowances.

create a bias tape circle

Step 2.4: The careful observer will notice that this is not the actual piece of bias tape that was used to face the neckline. I didn’t think my original picture was clear enough so I took another one with a shorter piece of bias tape.

Step 2.5: Pin your bias tape to the opening and sew it in place.

Step 2.5

Step 2.6: Fold the tape over to the other side of the garment and edge stitch in place.

Step 2.6

You are done and should now have a lovely looking bias tape bound opening!

Bias tape finished neckline!

I would love to hear from you whether you found this tutorial useful and which method is your favourite! Also, if you have any questions don’t hesitate to ask and I’ll do my best to help you.

60 comments on “Tutorial: How to perfectly fit bias tape to an armhole or neckline

  1. Amanda says:

    Thank you! This is fab. I never get my bias binding to be a perfect fit! You have solved my problem.

  2. sara says:

    I was looking on the web and found your instructions. I got it! Great pictures, great instructions – I sewed bias like a pro.:) Thank you, thank you, thank you.

  3. Thanks so much! My linen blouse neckline turned out perfect. Very good tutorial.

  4. lulu says:

    Method 1 is brilliant and you explained it very clearly. I just now tried it and it totally works–thank you so much for this tutorial, it was exactly what I was looking for! Now on to the other armhole….

  5. Jilly says:

    Thank you for this. I’m doing it right now on a top. Can’t wait to see the final result.

  6. Jessica says:

    Excellent tutorial…it helped save my sewing project…your technique worked perfectly! I really appreciated the RS/WS 45 degree diagram…I didn’t get it from the pics until I scrolled back up to the diagram. Thank you!

  7. […] followed the bias tips at Infectiousstitches.com and it came out pretty darn […]

  8. Maria says:

    Hello Emmely,

    I was very impressed with this tutorial. I used method 1 for my Sorbetto, and it worked very nicely. Thank you for your accurate instructions, and detailed photographs. Using your technique, the bias tape looks great! After completing my first Sorbetto (Size 0), it was a little tight, so I made a Size 2, lowering the underarm only. The Size 2 front looked a bit better than the Size 0 front (the darts were placed better ). However, in both the Size 0 and Size 2 backs, it is loose. I have no idea how to fix something like this. I am a beginner, and this is the first project I have made. I am asking for your help, hoping you will have an answer in fixing the fit in the back. I am new to sewing and need your expert instruction. I will appreciate your knowledge and guidance. Thank you.

    • Emmely says:

      Hi Maria,

      I am happy you found my tutorial useful! I am by no means a fitting expert and without seeing the garment it is difficult to determine what you should do but perhaps I can give you some tips.

      What is your cup size? Colette patterns are drafted for a C cup, so if your cup size is larger you might need to do a full bust adjustment (FBA). In that case you probably need to use the smaller size pattern and make the front larger with the FBA. If you choose a larger size to fit your bust and don’t do any adjustments the back will usually be too large. Here is a link to a tutorial on how you could do this type of adjustment. http://www.sewalongs.com/hawthorn/hawthorn-full-and-small-bust-adjustments

      Is it the back neckline that is too wide or the whole back piece?

      If it is just the neckline you might be able to solve this by taking out some fabric in the way illustrated in this tutorial. If you pin it out on the top you’ve already made you can check whether this improves the fit and how much you need to remove. http://gingermakes.wordpress.com/2013/09/06/by-hand-london-anna-dress-narrow-shoulder-adjustment/

      If it is the back that is too large but the neckline fits fine I would try to pin some of the excess out in the top that you’ve already made (the one that fits best). You should leave the neckline as it is (because that fits fine and if it fits fine you don’t want to mess with it!) and pint out a triangular wedge towards the hem. Do this on both sides of the top. If this does improve the fit you measure how much you took in on both sides, take the total and divide it by 2. This is the change you need to make to your pattern piece (since you’re working with only half back in the pattern). Remember that your pattern already has the seam allowance included so you need to take in your wedge starting from the stitching line and NOT from the seam allowance. Mark the stitching line on your pattern piece. Now you need to create a pivot point (in the first link they also use this for the FBA if it is unclear what I mean). Cut straight from the hem to the marked stitching line and also cut from the seam allowance to the stitching line. Do NOT cut through the whole piece. Now you can pivot the pattern to take out the wedge. This adjustment to the pattern does not change the stitching line but it does change your cut line so you’ll have to redraw it. You’ll also need to redraw the hem.

      If it is both the neckline and back that is too large I’d try pinning out fabric along the centre back to see if that improves the fit. If it does simply make the top narrower by cutting the pattern parallel to the centre back line. You will need to redraw the neckline (true it)and hem to make sure they still looks good when you cut your pattern piece from fabric. They need to make a right angle with the centre back line.

      Good luck!

      • Maria says:

        Thank you Emmely very much for helping me. I will try your suggestions to see if I can improve the fit. I have a feeling the back is too large and need to be taken in, Thank you again for your quick response and options.I am wondering now if anyone else has noticed or had this problem in the back, while the front looks good.

      • Emmely says:

        If the back really is too large, it is possible that the smallest size is not small enough for you. However, don’t forget that the Sorbetto is supposed to be a rather loose fitting top. There is no closure so you need to be able to fit it over your head. If you make it too fitted that might no longer be possible.

  9. Siri says:

    I just used this tutorial for armholes on a dress, it worked wonderfully and looks great!! Thank you for sharing this :)

  10. Lyric says:

    What a wonderful share. I’m excited to give it a try as bias binding and piping are my new best friends. As one who is off the electrical grid I’m going to have to get this into a pdf and/or Word document sew I will have it in the sewing studio when I need it.

    Thank you again.


  11. Awesome tutorial! Thank you so much. I am beginning to make my own clothes and this REALLY helped.

  12. jo says:

    What a great tutorial! Very clear photos and instructions, thank you! I am adding your blog to my Feedly :)

  13. […] because I was feeling lazy. If I make something like this again in the future, I’d like to finish a bias tape circle properly for a more invisible […]

  14. […] followed infectious stitches‘ tutorial (method 2) for measuring and applying the bias finish on the armholes – it […]

  15. Yasuko says:

    Glad I have found your site as I was wondering how to make bias for my sister-in-law’s dress!!

  16. You’re wonderful! Thanks for this :)

  17. […] 2.) A bias tape covered hem.  You can buy double folded bias tape anywhere they sell sewing supplies.  I get mine at Walmart.  Here are instructions for doing this kind of neckline. […]

  18. Maryellen says:

    I have been struggling with this and did not figure out a clean way to complete my armholes and necklines using my bias strips. Thank you, Emmely!

  19. Cindy Allen says:

    Omg! I can’t tell you how extremely helpful this tutorial has been for me and for my sewing life! The hours (days?) that I have wasted due to this problem but still never learning the proper way to do this with my own trial and error ( mostly error! )
    So grateful to you!

  20. Heather Jo says:

    I was serching for the clan finish with the folded bias. It seems like the constuction is same as what I was looking for. I guess I could use this technick for active short pants bottom opening hem. Thank you so much for good knowledge.

  21. Cindy Allen says:

    Hello again, adding to my previous comment, I just wanted to say that this has got to be the most GENIUS thing I have ever found in all of the sewing I have done. Still trying to figure out how you ever came up with this as I have never seen this done before. Thanks a million for taking the time to share this gem of wisdom.

  22. […] because I was feeling lazy. If I make something like this again in the future, I’d like to finish a bias tape circle properly for a more invisible […]

  23. Ourania Antonopoulou says:

    Thank you very much for sharing this tut,very kind of you.You really solved my problem with a blouse I am sewing .I am grateful

    • Emmely says:

      I am glad you found it useful! I often use this method instead of what is instructed in the pattern as I find it much easier.

  24. Sarah says:

    You mention this is for wovens, and that “other rules apply” to knits. What are those other rules? Trying to put bias around the neckline of a dress I’m making out of a knit fabric.

    Thanks for your help!

    • Emmely says:

      I’m sorry I’m a bit late in responding, I was away on holiday. For knit fabrics you do not cut the binding strip on the bias. The reason we cut on the bias with woven fabrics is that it gives the binding strip more flexibility and some stretch. For knit fabrics this isn’t necessary as they are already stretchy and flexible. For knit fabrics you cut the strip in the direction that has the largest amount of stretch (usually from selvedge to selvedge). It is also important to cut the strip shorter than the neckline and stretch it as you sew it to the neckline. This will prevent the neckline from sagging. How much shorter it has to be depends a bit on how stretchy the knit is. I hope this was still useful for your project!

  25. Rene says:

    I’ll have to try this next time I bind a neckline! It looks fabulous, you can barely see the seam at all. Here’s another trick — press in the curve. Once you have your bias tape made, gently press the tape and curve it as you go to more or less match the curve you’re going to sew it to (making sure that the inside of the curve is on the proper side to match the seam. It doesn’t work nearly so well if it’s backwards, for some reason. Ask me how I know…) Don’t press too hard–basically steam it with a bit of contact. When you pick it up, the bias tape will be curved, ready to sew in, with no risk of the bias tape flaring out or pulling in. It’s like magic!

  26. […] because I was feeling lazy. If I make something like this again in the future, I’d like to finish a bias tape circle properly for a more invisible […]

  27. […] tape made from left over pieces from cutting up the ‘too small’ slacks. Here’s a how to from Emmely of infectiousstitches you may find helpful if you ever want to use bias facing for your next sewing […]

  28. Russo says:

    GREAT TUTORIAL! It was so well explained. It will help people with even basic skill (me) use bias tape. Tank you.

  29. […] and CB seam meet perfectly with the v-neck. Sew remainder of facing to garment. Complete as usual, seaming ends of tape together where they […]

  30. After poring through almost 10 bias tape tutorials, all of which seemed to gloss over the all-important join, thankfully I found this tutorial with the very clever 45-degree angle join. Method 1 worked great on a vest made from a denim shirt with my self-made bias tape is on the outside of the garment. Thank you for taking the time to painstakingly take many illustrative photo and to clearly explain. I’ve subscribed and now look forward to reading the entire blog.

  31. Cheryl says:

    Thank you! This is a great explanation for me. Much appreciated!

  32. Kate says:

    I am here 8 years nearly to the day you originally posted this to say: thank you!! I am finishing a dress to wear to my friend’s wedding this weekend and your awesome “Method 1” tutorial is exactly what I needed.

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