All zippers come in different lengths. Even though zippers are typically measured from end to end, in reality, there are different ways of measuring different types of zippers.
This article discusses some of the most common ways of identifying the correct length of a zipper. These methods can be used to determine and take not the right measurement of the specific zipper you will need for your sewing project. Just don’t forget to check that the zipper is zipped up completely before you measure, no matter what specific type of zipper it might be.
How to Measure Open-Ended Zippers
To measure the length of a standard open-ended zipper, you should start from the top part of the slider down to the end of the open part excluding the fourth head tape. If you incorrectly include the fourth head tape, you might end up with a zipper whose length is shorter than what you like or need.
How to Measure Close Ended Zippers
For standard closed-ended zippers, you can measure their length starting from the top portion of the zipper slider down to the end of the bottom stop with the back head and forth head tapes excluded. Once again, including the back head or forth head tape in the measurement will result in a zipper that has a shorter length compared to what you need.
How to Measure Two Way Open Ended Zippers
You can measure the length of standard two-way open-ended zippers starting from the upper portion of the zipper slider down to the bottom tip of the reinforce tape to the end of the open part excluding the fourth head tape.
How to Measure Two Way Close Ended Zippers
Two-way close-ended zippers have two categories namely X shape and O shape. These two both have double zipper sliders. The primary difference is that the latter features two bottom stops in which the sliders are installed in a head-to-head relation. Meanwhile, the former comes with two stops wherein the sliders can be found in a bottom-to-bottom relation.
In a standard two-way close-ended O shape zipper, you can measure its length from the end of the one bottom stop to the end of the other bottom stop. Again, you shouldn’t include the back head tape and fort head tape.
In a standard two-way close-ended X shape zipper, the length can be measured starting from the upper part of one zipper slider to the upper part of the other slider excluding the back head tape and forth head tape once again.
Give Allowable Tolerance
There are different factors that can affect the natural tolerance of zippers and these include the techniques used, the speed of operation of the machine, and the tensility of the zipper chain during the manufacturing process. In general, the tolerance is proportional to the length of the zipper.
Unsure of the length of the zipper you need? You can go for zipper tape by the yard to stay on the safe side.