Look at the neckline of a well-made blouse and then at one that was rushed. On the first the binding is an even narrow line, flat all the way round the curve. On the second it puckers in one place, stretches out in another, and shows a ridge where two strips were joined.
A cream blouse hanging by a window with navy bias binding finishing the neckline and armholes
Bias binding is a strip of cloth cut at an angle so it stretches and bends round a curve. It finishes a raw edge neatly, with no facing and no extra bulk. That is why it is on almost every neckline, armhole and sleeve opening in a shop that stitches blouses, kurtis and kids' frocks.
It is also easy to get wrong, because the very thing that makes it useful, its stretch, is what ruins it when it is handled carelessly. This guide covers how to cut it, how to join the strips, and how to sew it on without stretching it.
In this guide you will find:
- Why bias binding puckers, stretches or shows a ridge
- What cut width to use for each finished width
- How to cut bias strips from a single piece of cloth
- How to join the strips and make the binding
- How to sew it to a neckline, an armhole and a hem
- How the fabric changes the binding you can use
Why Bias Binding Goes Wrong
Four reasons, and all four happen before the binding reaches the garment.
It Was Not Cut on the True Bias
True bias is 45 degrees to the grain. Cut at a different angle and the strip stretches less in some places than others, so it twists on the curve and will not lie flat.
It Was Stretched While Pressing or Sewing
A bias strip is easily pulled long. A binding that is stretched as it is pressed or fed through the machine shrinks back after sewing and pulls the neckline in with it.
It Was Cut Too Narrow
A binding that is too narrow cannot be folded over the raw edge with enough left to catch on the back. The stitching misses the fold, and the raw edge shows.
The Strips Were Joined With a Bump
A square seam where two strips meet leaves a hard bump that shows through the right side. Strips should be joined on the diagonal.
Cut Width for Each Finished Width
A double-fold binding is folded in four, so the cut width is four times the finished width. Work out the finished width you want on the front of the garment, then cut accordingly. These are working figures; confirm them on a scrap of the same cloth.
Finished width | Cut width | Where it is used |
|---|
0.25 | 1.00 | Fine edges, kids' frocks, sleeve openings |
0.375 | 1.50 | Blouse neckline and armhole, kurti neck |
0.50 | 2.00 | A contrast neckline, a visible trim |
0.75 | 3.00 | Hem binding on a light garment |
1.00 | 4.00 | A decorative border or a frill edge |
If the cloth is thick, add a little to the cut width, because a thicker binding uses up some of the width in the fold. If it is fine, a narrow strip is enough.
How to Cut Bias Strips
- Start from a square or a rectangle of cloth with a straight edge on the grain.
- Fold one corner over so the straight crosswise edge lies along the lengthwise edge. The fold is the true bias.
- Press the fold lightly, and open it out. This line is your first cut.
- Rule lines parallel to the fold, one cut width apart, and cut along them with shears or a rotary cutter.
- Keep the cloth flat on the table the whole time. A bias edge stretches if it hangs off the table or is pulled.
- Cut a little more than the edge needs. It is always easier to trim a long strip than to join a short one.
Joining and Making the Binding
A strip of navy cloth being drawn through a brass bias tape maker to make double-fold bias binding
- Place two strips at right angles, right sides together, with the ends overlapping to form a small square.
- Stitch diagonally across the square, from corner to corner, with a quarter inch seam.
- Trim the corner off to a quarter inch and press the seam open. The join lies on the grain of the strip, so it is flat and almost invisible.
- Press the strip in half along its length, wrong sides together, then fold both raw edges to meet at the centre line.
- A bias tape maker does this in one pull, and a press behind it sets the folds. Do not stretch the strip as you press.
- Keep the finished binding in a loose coil. Rolled tight on a card, it stretches and goes wavy.
Sewing It to the Edge
The edge decides how much binding to cut, and how it is eased:
Edge | Binding length | Method | Watch for |
|---|
Round neckline | Neck measure + 2.00 | Stay-stitch the neckline first, then bind | Ease slightly on the inner curve |
Armhole | Armhole measure + 2.00 | Bind the armhole flat before the side seams | Do not stretch the strip round the curve |
V neckline | Neck measure + 3.00 | Bind, mitring the point | Cut the point cleanly, no tuck |
Hem on a curve | Hem circumference + 2.00 | Bind, easing on the outer curve | The outer edge needs a little extra |
Sleeve opening | Opening measure + 2.00 | Bind flat, then close the underarm seam | Match the join to the seam |
- Stay-stitch the raw edge about an eighth of an inch from the cut line before binding, so the edge cannot stretch.
- Stitch the binding to the front first, in the fold line, then wrap it to the back and stitch again from the front, in the seam line.
- Ease the binding on a curve; never pull it. It should lie on the edge as if it was meant to be there.
- Press from the wrong side, lightly, with a pressing cloth. Do not stretch the neckline as you press.
The neck and armhole measurements this is cut for are in our blouse cutting measurement chart and the kurti cutting measurement chart. The allowance the edge is cut with is in the seam allowance guide for tailors.
How the Fabric Changes the Binding
- Cotton and poplin – the easiest cloth to bind. It holds the fold well and presses crisply.
- Soft cotton and mulmul – cut the strip a little wider and handle it gently; it stretches readily.
- Silk and satin – slippery, so pin and baste. Use a narrower finished width and test on a scrap.
- Georgette and chiffon – use a narrow binding, in a matching cloth or in self-fabric, and do not press hard.
- Heavy cloth – add to the cut width, and trim the seam allowance inside the binding to cut the bulk.
- Stretch fabrics – use a knit binding cut on the cross grain rather than a bias strip.
Which cloth suits which garment in the first place is covered in our guide to which fabric for which garment.
Bias Binding in Tailoring CAD
In tailoring CAD the binding strip is drafted from the length of the edge it finishes. The cut width, the length with the joining allowance and the grain line are printed on the piece in every size, so the strip is cut to the figure and not guessed at the table. Nobody measures a neckline with a tape to find out how long the binding should be.
Our tailoring CAD software page shows how the pieces, including the binding strips, are printed.
Questions Tailors Ask
What does cutting on the bias mean?
It means cutting at 45 degrees to the lengthwise and crosswise threads of the cloth. In that direction the cloth stretches and drapes, which is why it bends round a curve.
How wide should I cut a bias strip?
Four times the finished width you want to see on the front of the garment. A neckline binding that finishes at three eighths of an inch is cut one and a half inches wide.
How long should the bias strip be?
The length of the edge plus about two inches for the ends and the joins. Cut a little extra – it is easier to trim than to add.
Why does my binding pucker on the neckline?
Usually it was stretched while pressing or sewing, or the edge was not stay-stitched first. Stay-stitch the neckline, and ease the binding on without pulling it.
How do I join bias strips without a lump?
Place them at right angles, sew a diagonal seam from corner to corner, trim to a quarter inch and press the seam open. The join then lies flat on the grain of the strip.
Can I use ready-made bias tape?
Yes, for quick work and standard colours. A self-cut binding matches the garment exactly, which is why most boutique work is cut from the garment cloth.
Bind It Once, Bind It Flat
A bias binding is the small detail that tells a customer whether a garment was made carefully. Cut true to the bias, joined on the diagonal and eased on without stretching, it is the cleanest finish a shop can give.
Book a free demo – on-site or online, in your language, with no commitment. Bring a blouse whose binding never lay flat and we will work out the strip on screen.