Zipper Length

Definition and Overview

Zipper length is the specified dimension of a zipper required for the opening and closing section of clothing or bags. In many cases, it refers to the length of the interlocking teeth section, and it differs from the overall length measured to the ends of the left and right zipper tapes.

For closed-end zippers, the basic measurement is from the top stop to the bottom stop, while for open-end zippers, it is generally based on the top stop to the separating end. However, the measurement standard differs depending on the product and the manufacturer's notation, so check the specification sheet.

Components Related to Structure and Length

A zipper is made up of continuously arranged teeth, a slider that opens and closes the teeth, top and bottom stops that secure the ends, and tape. Open-end zippers have a separator at the bottom end for separating the left and right sides.

When selecting the length, also check the tooth size. Larger teeth make it easier to achieve strength and a more substantial appearance, but on thin fabrics or small openings, thickness and stiffness may stand out.

• Closed-end zipper: The bottom end is closed with a bottom stop, and the left and right sides cannot be separated.
• Open-end zipper: The left and right sides can be separated by the separator.
• Two way separator / double slider: A specification related to the number of sliders and the opening/closing direction, specified separately from the length indication.

Main Applications and How to Choose Specifications

For the front opening of pants, side or back openings of skirts and dresses, pockets, bags, and similar items, choose the length to match the designed opening dimension. Open-end zippers are used for applications such as front-opening outerwear that need a wide opening on both sides.

Decide by checking the opening stop position on the pattern, seam allowance, finishing at the top and bottom ends, and the overlap of facing and lining. Consider not only the required opening length after completion, but also ease of moving the slider and room for putting on and taking off.

Points to Note During Sewing and Washing

Sew the zipper tape securely into the seam allowance, keeping the needle away from the teeth and slider. If the tape waves after sewing, opening and closing will become heavy, so avoid pulling the outer fabric too much and baste while aligning the left and right positions.

For products that are washed during or after production, the opening may wave due to shrinkage or twisting of the outer fabric. Check the fabric shrinkage rate, washing conditions, and zipper type in advance, and if necessary, make a prototype and conduct washing tests.

Differences from Similar Terms

Zipper length is a specification for the portion used for opening and closing, and it differs from the overall length of the zipper tape. The tape may include extra length longer than the teeth section for sewing-in and end finishing.

Tooth size is a specification that indicates the size of the teeth and is a separate item from zipper length. A chain refers to continuous toothed tape, which may be processed to the required length and made into a zipper.

Frequently Asked Questions

From where to where is zipper length measured?

In general, for closed-end zippers, the teeth section is measured from the top stop to the bottom stop. For open-end zippers, the standard is often from the top stop to the separating end, but notation may differ as to whether the tape end is included. When ordering, check the measurement standard on the drawing or specification table.

Should I choose a zipper with the same length as the opening dimension on the pattern?

Not necessarily. The required zipper length changes depending on the seam allowance, finishing at the top and bottom ends, and the relationship with the facing or waist belt. Set the start and end points of the teeth on the pattern, and determine the length after checking operability and appearance with a prototype.