How to Measure a Zipper
There are two important measurements on every zipper – length (noted in inches or centimeters) and gauge, which is typically accompanied by a # next to it.
Both are equally important when it comes to determining the right zipper replacement.
This guide will show you how to measure both.
What is Zipper Gauge (aka Zipper Size)?
Also known as zipper size, the gauge of a zipper refers to the width of its teeth, in millimeters, when it’s zipped shut. Whenever you see a number and hash symbol (e.g., #2) next to a zipper, this is referring to the zipper’s gauge.
The larger the number, the heavier the gauge, and, therefore, the heavier the zipper.
How to Measure Zipper Gauge
Measuring zipper gauge is easy. Measure the zipper teeth, in mm, horizontally when the zipper is closed. Make sure you don’t include any tape in your measurement – it’s just the teeth you want to measure.
You can use a measuring tape, ruler, or digital caliper. If your measuring tool only includes cm and inches, convert them to mm to figure out the gauge (1cm = 10 mm; 0.25” = 6.35mm).
Some guides suggest looking at the back of the zipper's slider to determine the zipper gauge, but this isn’t the best solution. The letters and numbers on the back can mean a whole host of things, depending on the manufacturer.
The best - and most reliable - way to determine a zipper's gauge is to measure the zipper yourself.
How to Measure Zipper Gauge if the Zipper Won't Close
If you’re working with a broken zipper that no longer
closes, you can work out its gauge by measuring one side and doubling it. You might have to round up or down slightly (to account for any overlap that occurs when the teeth are closed), but it should be fairly clear what the gauge is based on the measurement of a single side.
How to Measure Zipper Length
Generally, measuring the length of a zipper is easier than measuring the gauge of a zipper.
Zipper length is often measured in inches. The guidelines for measuring a zipper's length differ slightly based on type of zipper.
Regardless, you never include any zipper tape where there’s no chain in your measurement. To put it another way, zippers will always have some extra tape at the top and sometimes on the bottom, which is usually for cutting and sewing depending on the project. You don’t include this in your length measurement, as it’s essentially “waste” material in this regard.
Measuring Closed-End Zipper Length
Closed-end zippers are pretty easy to measure because they have obvious ends.
Measure the length from the top of the top stop to the bottom of the bottom stop to get the required length.
Measuring One-Way Separating Zipper Length
Also known as open-end zippers, these are just as simple to measure.
Go from the top of the top stop to the bottom of the retainer box, which is the part that keeps the zipper on its chain.
Measuring Two-Way Separating Zipper Length
Two-way separating zippers don’t have retainer boxes at the
bottom, as the second slider covers this purpose.
As such, you’ll want to measure from the top of the top stop to the bottom of the reinforcement tape.
Measuring Head-to-Head (Two-Way Bag-Style) Closed-End Zipper Length
Two-way bag-style zippers are closed-ended, and similar to one-way closed-end zippers, they are measured from end to end from each stop.
Unlike one-way closed-end zippers, however, these zippers have a bottom stop at each end, as opposed to a bottom stop at one end and top stops at another.
Measure from the top of one bottom stop to the bottom of the other bottom stop.
Ready to Shop?
Now that you know how to properly measure zipper gauge/size and zipper length, you can shop for what you need.
Our helpful shop filters will allow you to segment your searches by gauge and length.
As Seen In:
Let customers speak for us
I have never been disappointed with quality of products or service.
Ordered custom length zippers before. Good Service. Good Quality. Zippers arrived shortly after ordering.
It is nice to have a zipper ease stick on hand. I feel a smoothly operating zipper extends its lifespan. This stick is more like a beeswax than a flaky bar soap consistency.
Basically I got the "grab bag" to have a few in the sewing chest in case of need. What arrived is a good assortment of lengths and colors. Three were heavy duty and separatable, they ranged in length to short like for a zippered pocket, to long like you would use for a cushion slip cover. Some were metal teeth and some were resin.
I was in a pickle because I had a zipper slider that I needed to replace that I had never seen before. I googled ‘zippers’ and saw the catchy ZipperShipper name. I told them my predicament and they said ~ oh! This is the one you need! ~ Sure enough they were right! Many thanks to the team! I ordered a few extra for future use🤓
Zipper Shipper is a great resource! Good quality and excellent delivery service.
i recieved the zipper and havent had time to put it in yet but looks like a nice zipper
The zippers I ordered were shipped quickly. The colors were true, size exact.
I already need more!
Thank you
The colors and quality are amazing.
Good to know I can get what I need here.
Always wonderful to work with- I’ve been ordering with them for many years and have always had great experiences with them
From the quality, customer service and prices, they are all great
I bought a length of sturdy #8 zipper and four sliders, to fix a worn-out zipper on an old but still-useful backpack. (I think the original pack used #5 zippers; most of them still work but the big compartment gets a lot more use). Your website has great info about best weights to use, and how to make a bag-type double zipper, and great selection of sizes (and colors for lighter weights), and fast delivery. As for DOING the replacement, I find the original zipper was sewn early in the assembly, ends covered by many layers of stiff fabric and webbing! It's going to be a tough reach for our little sewing machine. Worst case I'll hand sew it (doesn't have to be beautiful)...I'll figure it out. Your brand-new zipper is my best possible starting point.
I never even knew this type of zipper existed, until I was asked to replace a broken slider. I went right to your website, found what I needed, and also found one of your videos explaining how to replace it. Thanks!!
