Manufacturer · Fashion Accessories
Bias binding is a tape cut on the diagonal of the fabric – at 45° to the threads. This lets it stretch slightly and curve around rounded edges without forming pleats. It is used to finish necklines, armholes, hems and the edges of bags and home textiles.
What bias binding is and why it is cut on the diagonal
In ordinary woven fabric the warp and weft barely stretch. On the diagonal, however, the fabric "gives" – the cells of the weave distort into a diamond. This natural elasticity lets bias binding follow the curve of a neckline or the rounded corner of a pocket. A straight tape cut along the grain would gather or leave ripples.
Ready-made bias binding is most often sold pre-folded: both edges are folded in towards the centre (single-fold), and with double-fold binding the tape is folded once more almost in half. This gives the sewer a ready-made binding that simply wraps around the fabric edge.
Types of bias binding
- Cotton – matt, pleasant to the touch, suitable for cotton and linen items, childrenswear and aprons.
- Polyester – does not shrink, colourfast, good for series production and items washed often.
- Satin – glossy, for formalwear, nightwear and lingerie.
- Elastic (knitted) – for jersey and swimwear, where more stretch is needed than woven bias binding offers.
- Printed – check, dots, stripes; a decorative edge binding on the garment.
Bias binding widths
The width is stated in two ways – unfolded and folded. When ordering, specify which you mean, because the difference is twofold.
| Finished binding (folded) | Typical use |
|---|---|
| 6–10 mm | fine necklines, childrenswear, lingerie |
| 10–15 mm | necklines and armholes of blouses and dresses, seam finishing |
| 18–25 mm | aprons, kitchen textiles, bag edges |
| 30 mm and over | blankets, covers, decorative bindings |
The more curved the line, the narrower the tape should be – wide bias binding is hard to bend around a small radius.
How to sew bias binding – step by step
Two methods are most common: visible binding (the tape wraps the edge and is visible on both sides) and a hidden facing (the tape is turned completely to the inside).
Visible binding
- Trim the edge of the item without a seam allowance – the binding will be the finish itself.
- Unfold one side of the tape and place it right sides together with the item, edge to edge.
- Stitch along the first fold. On curves, do not stretch the tape on concave lines (neckline) and stretch it slightly on convex ones (rounded corner).
- Turn the tape over the edge to the wrong side and secure it with pins or clips.
- Topstitch from the right side right next to the seam ("stitch in the ditch") or along the edge of the binding.
Hidden facing
The tape is sewn right sides together, the seam allowance is trimmed and clipped on the curves, and then the tape is turned completely to the inside and topstitched. Only a thin line of stitching shows on the outside. The method is typical for necklines of collarless blouses.
In series production the binding is most often applied in one pass with a binder attachment (folder) on the machine, which folds the tape automatically. In this case the width of the tape must match the binder exactly.
How to choose bias binding
- The material should be compatible with the fabric in washing and shrinkage – cotton bias binding on polyester may pucker after the first wash.
- The weight should be similar to or lighter than the fabric; a stiff binding on thin viscose looks out of place.
- Choose the colour against a fabric sample, especially for contrast bindings.
- For jersey, choose a knitted or elastic tape instead of woven bias binding.
If you need a straight, non-stretch tape for reinforcement rather than binding, herringbone tape is more suitable; for a glossy decorative binding see satin ribbon. You will find all types in our tapes and ribbons section.
How much bias binding you need
Consumption is calculated from the length of the edge to be finished, plus an allowance for joins and ends. For a neckline, measure along the seam line, not the edge of the pattern. Add about 5–10 cm for starting and finishing the binding, and in series production a reserve for machine set-up and trial pieces. If the binding is applied with a binder, the tape comes on a roll and is fed continuously, so joins are avoided entirely. It is also important to plan the colour for the whole batch at once: tapes from different dye lots can differ in shade, which is noticeable with contrast bindings on neighbouring garments on the shop rail.
Common mistakes with bias binding
- Stretching the tape on a concave neckline – the edge gathers and the neckline feels tight.
- Joining at a right angle – bias binding joins are made on the diagonal to avoid a bulky spot.
- Too wide a tape for a small radius, for example on childrenswear.
- Skipping a test wash when combining different materials.
Bias binding and other tapes from Polkom
Polkom is a manufacturer and wholesale supplier of sewing accessories from Sofia with over 30 years of experience. We help garment factories and brands choose the width, material and colour of tapes, including matching to a fabric sample. Send us the details of your garment via our contact page – we will propose a suitable article and a sample.
