To measure a finished zipper, first identify its configuration and the endpoints used by the manufacturer. In standard YKK diagrams, dimension A is measured with the zipper fully closed and laid flat. Tape extensions have separate dimensions, B and C. An order for a “30 cm zipper” can therefore be ambiguous without a drawing.
Zipper length and tape extensions
In YKK diagrams, A denotes the product length between endpoints determined by its construction. B describes the top tape extension; C describes the bottom extension where the diagram includes one. B starts at the top stop. On an ordinary closed-end zipper, C starts at the bottom stop. The tape end and the chain end are different reference points.
Keep these labels on your sketch. Do not treat A + B + C as a universal formula for overall tape length: the upper endpoint of A may be on the slider body, while B starts at the stop. If cutting or packing requires an overall dimension, measure it separately and label its endpoints.
Where to start and finish measuring
The official YKK How to Measure a Zipper diagrams distinguish several configurations:
- Ordinary closed-end zipper with one slider: A runs from the top of the slider body to the end of the bottom stop.
- Ordinary open-end zipper: A runs from the top of the slider body to the end of the retaining box.
- A configuration whose top stop does not enter the slider: the upper measurement starts at the stop, following its specific diagram.
The pull tab is not the top edge of the slider body. For double-slider, reversible and special configurations, use their own diagram: slider and end-component positions change the reference points. Apply YKK diagrams to the corresponding YKK configuration; check the documentation for another manufacturer’s product.
How to record a sample measurement
- Identify whether the zipper separates completely, how many sliders it has and how they are arranged. Find the item code or photograph its markings.
- Close the zipper completely and lay it flat, as instructed in the YKK manual’s Zipper Dimension section. Smooth the tape without stretching it.
- Mark both endpoints of A on a photograph. Measure in millimetres and record which diagram you used.
- Record the required tape extensions and their reference points separately. Label concealed sections of an already sewn-in sample as unmeasured.
- Compare the result with the assembly drawing. Check where seams, stops and separating components will sit after sewing.
An example of an approval record
An illustrative enquiry for an ordinary closed-end zipper could state: “A = 300 mm, from the top of the slider body to the end of the bottom stop; B = 25 mm; C = 20 mm; B/C endpoints shown on sketch; one slider.” These are teaching dimensions, not an available item or standard DELIM sewing allowances.
Add the chain series, colour, slider version and tolerance requirements. Agree the permitted length variation for the particular model; a nominal 300 mm does not automatically mean zero deviation. The YKK manual includes a tolerance table with an exception for special products. Do not extend that table to every other manufacturer’s zippers.
What to send to DELIM
Send photographs with measurement points, an assembly sketch, the item code or known markings, dimensions A/B/C, quantity and required configuration. If ordering continuous chain, describe how finished zippers will be made: compatible sliders, end components and finishing operations need to be agreed. A cut length of continuous chain does not by itself specify finished dimension A.
Start with DELIM’s zipper range. Use the guide to zipper element types to identify the chain construction and the YKK slider selection guide for components. A manager will confirm availability, samples and supply terms for your enquiry.