How to Finish a Neckline or Armhole with Bias Binding (Step-by-Step Tutorial + Video)
Bias binding is a lovely way to finish edges such as necklines and armholes, especially on lighter weight garments where you don’t want the extra bulk of a facing.
In this tutorial, I’ll show you how to finish a neckline or armhole using single fold bias binding, hiding it on the inside of the garment. I’m demonstrating on the Skye sundress sewing pattern, but you can use this method on lots of different sewing projects, including the Leah top + dress and Marnie blouse.
Once you’ve sewn bias binding a couple of times, it quickly becomes one of those techniques that feels surprisingly satisfying. Promise!
What is bias binding?
Bias binding is a strip of fabric cut on the bias grain – in other words, at a 45° angle to the selvedge – folded lengthways, and used to finish raw edges that aren’t attached to anything else. The bias cut allows it to mould around curves without puckering.
You can either buy ready-made bias binding or make your own from fabric scraps – check out our tutorial on how to make bias binding.
Single fold bias binding has the long raw edges pressed in towards the centre. This is what I’ll be using in this tutorial. It’s stitched to the edges of the neckline or armhole, then pressed to the inside and edgestitched down to conceal the raw edges, hiding the binding on the inside of the garment.
Double fold bias binding, on the other hand, is simply single fold binding that’s been pressed in half lengthways. It’s often wrapped around the raw edges, leaving it visible on both sides – you could use it on the loose edge of a jacket facing, for example. Here’s how to finish the edge of a facing with double fold bias binding.
Why use bias binding?
Bias binding is a lovely finish when:
- A neckline or armhole doesn’t use a facing
- You want a lightweight seam finish
- You’re sewing with delicate or drapey fabrics
- You want the inside of your garment to look just as pretty as the outside
It’s especially lovely on spring and summer sewing projects like tops, blouses, sundresses, and camisoles.
How to finish an edge with bias binding
Step 1: Pin the bias binding to the garment
Open out one folded edge of the bias binding and pin it to the raw edge you’re finishing, right sides together. Start at an inconspicuous area – the neckline opening if it has one, or the shoulder seam on a neckline if it doesn’t, or the underarm seam on an armhole – and leave 10-20mm (3/8-3/4in) of binding extending past the starting point.
If you’ve staystitched the edge you’re binding, check the channel of the binding that’s closest to the edge is sitting just below the staystitching so the stitches will be hidden once sewn.
Step 2: Edges without openings: Join the ends
If you’re sewing an armhole or neckline that doesn’t have an opening, you’ll need to join the ends of the binding together before you stitch it to the garment.
Mark the points where the ends of the binding overlap, pin and stitch them together at this point, keeping the rest of the garment out of the way.
Trim the seam allowances and press them open.
Then pin the remaining section of binding to the garment edge.
Step 3: Stitch the binding in place
Sew the binding to the garment, positioning the needle exactly along the crease of the binding that’s closest to the raw edge.
Take your time here, especially around curves. I find sewing slowly makes it much easier to keep the stitching line neat and accurate. You can pause with the needle down if you need to adjust the layers or check the seam.
Step 4: Trim the seam allowances
It can be helpful to trim the garment seam allowance layer so it’s slightly narrower than the binding. This helps reduce bulk and can make it easier to turn the binding to the inside of the garment.
If you have any particularly tight curves, you may want to clip into them to help the seam sit smoothly once turned to the inside.
Step 5: Understitch the binding
Fold the binding away from the garment, towards the seam allowances. Press if necessary to get a nicely defined seam.
Understitch the binding to the seam allowances close to the seam line, gently pulling the fabric away from the seam as you sew.
If you’re new to understitching, it’s absolutely worth learning – it helps keep the binding neatly rolled to the inside so it doesn’t peek out while you’re wearing the garment.
Step 6: Turn the binding to the inside
Press the binding to the inside of the garment, rolling the seam line slightly inward so the binding isn’t visible from the right side.
If the edge you’re finishing has an opening, and the binding tails are loose, press them under first so they end up concealed under the length of the stitched binding.
The lower fold of the binding should still be pressed under. Pin this fold to the inside of the garment.
Step 7: Edgestitch the binding
Edgestitch close to the pinned binding fold to secure it in place. The easiest way to ensure you’re catching the loose fold of the binding in the stitching is to sew with the binding face up. However, you may get a neater result on the outside of the garment by sewing with the garment side face up – in which case, feel through with your fingers to check you’re catching the fold in the stitching.
Give everything a final press to neaten it up.
And that’s it – beautifully neat bias binding with all the raw edges tucked away nicely inside.
Tips for sewing bias binding neatly
Use lightweight fabrics
Bias binding works especially well on lightweight fabrics like cotton lawn, viscose (rayon), and linen blends.
Press as you go
Bias binding behaves much better when pressed regularly throughout the process. A quick press after each step really improves the final finish.
Sew slow
Take your time to get your stitching in the right place. Be careful not to pull the project as you sew, or you could end up with rippled edges.
Don't skip understitching
Honestly, understitching is the secret sauce here. It helps stop the binding rolling outward and gives a much cleaner finish.
Watch the video tutorial
If you prefer learning visually, we’ve also put together a step-by-step video tutorial showing exactly how to use bias binding to finish the neckline and armholes on the Skye sundress sewing pattern.
Ready to practise sewing bias binding?
Bias binding can feel a little fiddly the first time you try it, but once it clicks, it’s such a useful technique to have in your sewing toolkit.
If you'd like a gorgeous project to practise on, take a look at the Leah top + dress sewing pattern – it’s perfect for showing off a beautifully finished neckline and armholes (and there’s a whopping SIX variations you can sew!).
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