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070: How to Sew Buttonholes on Knit Fabrics

with special guest Melanie Keane

In this article I want to cover a topic that I know a lot of sewists find challenging and sometimes scary and that is sewing buttonholes on knit and stretch fabrics. I know this can be incredibly frustrating and a bit intimidating.

My good sewing friend, Mel Keane, decided to tackle buttonholes on stretch fabrics for her recent project to make the popular Marlo Sweater (which in the UK we'd call a cardigan!). It is on my list to make and so I asked her about her experiences and any tips or recommendations she could make.

In this article:

Why are Buttonholes Such a Nightmare?

Firstly, let's talk about why buttonholes can be such a tricky business. If you have struggled to sew them then it's not surprising as there are quite few aspects that can make them challenging:

  • Lots of stitches in a small space - buttonholes use zig zag stitches sewn closely together to bind the edges of the buttonhole which means lots of stitches in a small space that can get jammed up

  • Four elements to each buttonhole - each one has 4 sides to be sewn that ideally all have to be consistent

  • Lots of movement - to create the buttonhole the machine has to move the fabric around in lots of small increments which means if your fabric stretches or catches it can impact the success of the buttonhole

  • Calculating the right size - if you have a non-computerised machine it's likely you'll need to calculate the right size for your buttonhole and that can be trickier than you think

  • Difficult to unpick - lots of small stitches mean if it does go wrong unpicking is definitely not for the faint-hearted

  • Hard to start part way through - if you have a computerised machine with one-step buttonholes, if you run out of thread part way through you have to unpick and start from scratch

  • Mistakes are prominent - by nature buttonholes are often in obvious places on your garment so any mistakes can be more easily seen

  • Challenging to cut - buttonholes require you to cut the fabric and it's easy to slip and cut too far if you're not careful

And then if you factor in doing this on knit fabrics. These fabrics have a tendency to stretch out just when you don't want them to, causing inconsistent or misaligned buttonholes.

The right tools and preparation

Buttonhole feet for computerised and non-computerised machines
Buttonhole feet

There are a number of tools that will help you when creating your buttonholes:

  • scraps of fabric same as or similar to your final garment - these are to test out your buttonhole settings

  • non-stretch interfacing - this helps to stabilise the fabric

  • sewing machine and thread - to sew the buttonhole

  • appropriate sewing machine needle for your fabric - for stretch fabrics use stretch or ballpoint needles

  • buttonhole foot - most machines with a buttonhole stitch option will have a rectangular buttonhole foot

  • button - pick your buttons before making your buttonholes to ensure they are the right size

  • ruler or tape measure - used to calculate the size of your buttonhole if using a non-computerised machine and to mark your buttonhole placement

  • marking tools - chalk or frixion pen - used to mark the positions of your buttonholes. Pins can be used as an alternative

  • pins - used to mark buttonhole positions and to assist with cutting buttonholes if using an unpicker/seam ripper

Tools for sewing stretch buttonholes
Tools for sewing stretch buttonholes

Some additional optional items that will help give a professional finish:

  • pen and paper - to record the size of your buttonhole measurement if calculating manually and to keep track of your test combinations

  • Fray Check - used to minimise fraying of the fabric at the cut edges

  • buttonhole chisel - an alternative tool for cutting your buttonholes

  • unpicker/seam ripper - can be used to cut the buttonhole opening and also unpick any mistakes

  • Stitch n Tear - an additional stabiliser that can help when working with stretch fabrics

How to sew buttonholes on knit fabrics

Now you have your tools let's go through the steps to create your buttonholes.

Testing is your best friend when it comes to buttonholes. As we mentioned they can be a bit temperamental and each fabric will behave in its own unique way.

Buttonholes tested on scrap fabrics
Use scraps to test settings

Test out different options to see which look the best. Take notes so that you can replicate which settings and combinations you like the best.

If you are using a computerised machine, it is likely that the buttonhole foot will have room in it for you to put your button. This will then calculate the size of the buttonhole for you.

If you have a non-computerised machine you can calculate your buttonhole size by measuring the diameter of your button and adding 1/8" or 3mm.

NOTE: If your button is thicker than 1/8" or 3mm then add the thickness of the button instead.

Prepare your fabric

  • To get started grab your scrap fabric and make sure it is big enough to fold over and leave you room to test your buttonhole.

  • Cut a piece of non-stretch interfacing wider than your button and at least 1 inch longer than your button diameter.

  • Iron or tack it to the wrong side of your scrap where you plan to test your buttonhole.

  • Fold the fabric, sandwiching the interfacing in the middle

  • If you have Stitch n Tear, cut a piece about the same size as your interfacing and place it under your scrap fabric. You can pin or tack it in place if you want to.

Marking your buttonhole

Non-computerised sewing machines

Marking your buttonhole
Marking your buttonhole

If you have a non-computerised machine you can calculate your buttonhole size but measuring the diameter of your button and adding 1/8" or 3mm. If you button is thicker than 1/8" or 3mm then add the thickness of the button instead.

On your scrap fabric mark the length of your buttonhole. Make the top and bottom lines long so that you can see them even when the buttonhole foot is attached.

Computerised sewing machines

If you are using a computerised machine, it is likely that the buttonhole foot will have room in it for you to put your button. This will then calculate the size of the buttonhole for you.

In this case you just need to mark the starting point for your buttonhole.

Setting up your machine

Now you have your fabric marked up, you are ready to take it to your machine.

If you haven't already done so, change the foot on the machine to the buttonhole foot. If you have a computerised machine remember to put your button into the foot before attaching it to the machine.

Make sure that your needle matches your fabric. If you have stretchy fabric try using a ballpoint or stretch needle. For more information on sewing machine needles check this Guide to sewing machine needles.

Choose your buttonhole stitch setting. If you have multiple options, decide which one you are going to test first.

4 Step Buttonhole Machine setting
4 Step Buttonhole Machine setting

If you have a non-computerised machine, pick the first setting for your 4-step buttonhole.

Put your fabric under the foot making sure your Stitch n Tear is under your fabric if you are using it. Put your needle into your fabric at the start point of your buttonhole (see diagram above). Put your presser foot down making sure that your fabric is lined up with the direction you want your buttonhole to be sewn.

If you are using a computerised sewing machine, put your foot down and let the machine work it's magic. You might want to gently support the fabric but let the machine guide it.

If you are using a non-computerised machine you have a bit more work to do:

  • do approximately 6 stitches in position a

  • make sure the needle is out of the fabric and change the dial to position b

  • sew until you get to the end of the length of your buttonhole

  • make sure the needle is out of the fabric and change the dial to position c (this is often the same setting as a)

  • do approximately 6 stitches

  • make sure the needle is out of the fabric and change the dial to position d

  • sew until you get to the start of the length of your buttonhole

Cut your threads and move onto checking your results.

Check your results

How does it look? Are you happy with the stitches? If so, you can move on to cutting your buttonhole. If not, decide what changes you'd like to make and try again (see tips for fixing problems for more details).

If you used Stitch n Tear, you can now remove that from the back of your sample by tearing it away.

If you are using an unpicker or seam ripper to cut your buttonholes, first add pins across the top and bottom of your buttonhole inside the stitching lines. This will help to stop you accidentally cutting too far.

Insert your unpicker and gently start to cut. Try to keep to the centre to avoid cutting your stitches.

If you are using a buttonhole chisel, place your sample onto the cutting board or a cutting mat and use the chisel to press down in the centre of the buttonhole to cut it.

Test your buttonhole to make sure your button fits through it. It should be snug but not too tight.

Tips for fixing problems

I think there is a correlation between the quality of a sewing machine and the quality of the buttonholes it produces. On my very basic Brother machine I found that the buttonhole foot wasn't as effective at moving the fabric and I did have to assist it particularly on the second stage of the manual buttonhole.

If you find the thread is bunching up on a non-computerised machine, try doing fewer stitches on the first position and assisting the foot and fabric at the start of each new stage.

Stabilisers make a big difference. Try different combinations of interfacing to see which gives you the best results with your particular fabric. Stitch n Tear is also a great option and not very expensive so worth the investment.

Buttonhole stitch options on sewing machine
34 - Stretch buttonhole option

If you have options to change the density of stitches, try those too. Some machines have stretch buttonhole stitch options.

If you have a computerised machine and find that your buttonhole seems to be the wrong size, check that you have pulled down the lever that tells the machine how long the buttonhole needs to be - it's usually located to the right of the presser foot.

Tips for sewing on your final garment

Once you have settled on your perfect combination of settings and stabilisers you now need to mark your final buttonhole positions on your garment. Don't feel you need to blindly follow the pattern's given positions. Try on your garment and pin where you want the buttons to go. This way, you customise the fit to your unique body shape.

Mel uses a pin to mark exactly where the needle will go down to start your buttonhole. This is really helpful when you want to line up several buttonholes as you can pin and check the start points before you take it to the machine.

She suggests that if you're using a plain-coloured fabric, matching your thread colour is really beneficial as using contrasting thread will make any mistake glaringly visible. If you are just trying this for the first time consider using patterned fabrics as they are more forgiving.

Another option to extend the life of your finished buttonholes is to apply Fray Check to neaten up any loose ends and strengthen the buttonhole. A small bottle can last you ages as you only need a drop!

Bonus Tip: Button position on stretch fabrics

Mel also had a brilliant tip about button placement. She places her buttons slightly higher than the buttonhole. Why? Because stretch fabric tends to pull down over time. Placing the buttons higher keeps everything lined up nicely.

If you'd like to listen to my full chat on this topic with the lovely Mel, click the button below or look for Sew Mindful on your favourite podcast app:

In this episode you'll hear:

  • [00:01:51] Introducing Melanie Keane

  • [00:03:08] Update on Knitting and Stitching Show

  • [00:06:06] Mel's project

  • [00:07:41] Challenges of sewing buttonholes

  • [00:09:53] Buttonhole stitch settings

  • [00:14:10] Lessons from the Marlo Cardigan

  • [00:16:14] Mel's first secret ingredient

  • [00:21:22] Mel's second secret ingredient

  • [00:23:41] Connect with Mel

If you do try these tips then please do get in touch and let me know what you think. And if you would like more help with any of the aspects mentioned in this article or this podcast episode then I would love to hear from you so do please email me at Thanks for taking the time to read this article and I hope you find some useful tips that you can apply.

Links and resources mentioned in the podcast episode

Connect with Melanie Keane:

Instagram: @melaniekeane

Sharing is caring - reviews

If you found this article helpful then please click the heart icon below to let me know and I'll create more content like this. And you can also use the icons in the footer if you want to share this with other sewing friends. If you enjoy this podcast episode please be sure to share it and to leave a review in your favourite podcast app to help others find us.

Get in touch

I always love to hear about you trying out what you pick up from these articles and episodes so do let me know:

Thank you so much for listening and for all your support. x

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