Manufacturer · Fashion & Home Accessories
Zip length is measured from the top of the slider (with the zip closed) to the bottom of the bottom stop – or to the end of the box on an open-end zip. The textile tape that extends above and below the chain is not included. This is how length is stated in catalogues and in orders.
How to measure zip length – the basic rule
A zip has two different "lengths": the length of the chain (the area with teeth) and the overall length of the tape. The commercial, nominal length always refers to the working part – the section in which the zip actually opens and closes. The tape usually continues for about 1–2 cm above and below so that there is room for the seam, but it is not included in the measurement.
- Close the zip completely so that the slider rests against the top stops.
- Lay it on a flat surface without stretching it – especially nylon coil zips, which stretch slightly.
- Place the zero of the ruler at the top of the slider (not the puller).
- Measure to the bottom of the bottom stop (closed-end zip) or to the end of the box (open-end zip).
- Round to a whole centimetre – zips are ordered in centimetres or inches.
Measuring by zip type
Closed-end zip
Measure from the top of the slider to the bottom of the metal or plastic stop that joins the two halves. This is the simplest case and applies to trousers, skirts, pockets and cushions.
Open-end zip
Measure from the top of the slider to the bottom of the box (the plastic or metal part the pin goes into). Important: an open-end zip cannot be shortened at the bottom, because that is where the separating mechanism is. That is why the length must be specified exactly.
Two-way zip
On a two-way zip, the two sliders are brought together at one end and the measurement is from the outer end of the top slider to the bottom of the box or stop. On a two-way zip closed at both ends (for holdalls, suitcases), measure between the two end stops.
Invisible zip
An invisible zip is measured by the same rule, but bear in mind that when it is sewn in, the last 2–3 cm above the bottom stop are not sewn all the way because of the slider. That is why an invisible zip is taken about 2–3 cm longer than the opening.
How to work out the length you need from the product
If you are taking the measurement from the pattern rather than from an old zip, measure the opening the zip will be sewn into after marking the seam allowances. A good rule:
- Closed-end zip in a seam (skirt, dress): the length of the opening, and for an invisible zip – 2–3 cm more.
- Open-end zip for a jacket: the distance from the top edge of the collar to the bottom edge of the hem, minus about 1–2 cm (depending on how the edges are finished).
- Pocket: the length of the pocket opening, nothing extra.
- Bag or pouch: the length of the top edge; if the zip has to go "round" the corners, measure along the perimeter with a soft tape measure.
Standard zip lengths
| Product | Zip type | Usual length |
|---|---|---|
| Women's trousers, jeans | Closed-end, No. 3–5 | 12–20 cm |
| Skirt | Closed-end or invisible | 18–22 cm |
| Dress (back) | Invisible | 40–60 cm |
| Sweatshirt | Open-end, No. 5 | 50–70 cm |
| Jacket, parka | Open-end or two-way, No. 5–8 | 60–90 cm |
| Cushion | Closed-end | to the width of the cover |
The table is approximate – the exact length always depends on the size and the pattern. In series production, each size in the size range usually gets its own zip length, especially for jackets.
Centimetres or inches
In Europe zips are ordered in centimetres, but some catalogues, especially for branded zips, use inches. 1 inch = 2.54 cm, i.e. 7" ≈ 18 cm, 9" ≈ 23 cm, 22" ≈ 56 cm. When writing an inquiry, state the unit of measurement explicitly to avoid any discrepancy.
Common measuring mistakes
- Measuring the whole tape including the end pieces – the result is a zip 3–4 cm too long.
- Measuring from the end of the slider's puller rather than from its body.
- Measuring a stretched nylon coil zip – on long zips the error can exceed 1 cm.
- One length for all jacket sizes – on the large sizes the zip ends up too short.
How to measure an old zip you are replacing
When a zip is being replaced with an identical one, it is safest to measure the old one before unpicking it. Besides the length, note the other parameters too – otherwise the new zip may be the same length but not fit.
- Size: measure the width of the closed chain in millimetres – about 3, 5, 8 or 10 mm.
- Type: metal, nylon coil, moulded or invisible; open-end, closed-end or two-way.
- Tape width: matters if the seam is visible on the outside and must fall in the same place.
- Slider: auto-lock or non-locking, with one or two pullers.
- Colour of the tape and teeth: ideally with a daylight photo or a physical sample.
Non-standard lengths and ordering
Besides standard lengths, many of the zips in the zips category are also produced in custom lengths – convenient for runs where each size has a different measurement. For closed-end applications there is also the option of nylon coil zip by the metre, from which lengths are cut and fitted with sliders. For metal zips it is better to order the exact length, because shortening is more labour-intensive.
Polkom – zips in the exact length
Polkom is a manufacturer of accessories for fashion, furniture, footwear and bags, based in Sofia, with over 30 years of experience. We send samples before the production run starts so that you can check the length and colour on the product. Send an inquiry with the zip type, size, the lengths per garment size and the fabric colour.
