Zipper Components

For most zippers, the right side of the zipper is the side that has the teeth/elements, slider, and pull visible.
Tape: fabric portion of the zipper that is sewn into your project. Pre-made zippers generally have a tape extension of ~0.75” on either end without any teeth.
Elements/Teeth: metal or plastic pieces attached to the tape that interlock to form a chain (in metal and molded plastic zippers) or coil (in nylon coil zippers)
Slider: moves up and down the zipper to interlock or separate the elements/teeth. The rounded end (head) has two channels and the flat end (tail) has one channel. You can usually find the zipper size stamped on the back/wrong side of the slider.
Pull: tab attached to the front/right side of the slider that you pull to open and close the zipper; available in many different shapes and sizes.
Stops: metal or plastic pieces on ends of the zipper tape that prevent the slider from coming off the zipper
Retaining box and insertion pin: instead of a bottom stop, separating zippers have a retaining box and insertion pin that must align in order to close the zipper.

Teeth/Element Materials

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Note: YKK is widely known as the most dependable zipper manufacturer. They produce over half of the zippers in the world each year! When in doubt, I recommend going with YKK.

Nylon Coil

A nylon coil zipper is made from a continuous coil of nylon monofilament that is sewn to a zipper tape. Nylon coil zippers are the most versatile zippers: they are lightweight and flexible, which makes them excellent for inserting along curves. They are also very easy to cut to size and sew through without damaging your machine. They work especially well for light to medium-weight fabrics and projects that might apply pressure to the zipper (e.g., a fitted dress or an overstuffed toiletry bag). Coil zippers are not as durable as the other options below.

Molded Plastic

Molded plastic zippers (called Vislon by YKK) are formed by molding (not sewing) plastic directly onto the zipper tape. These zippers have large, stiff teeth that interlock like puzzle pieces, which makes them more bulky and thus best for straight seams. Molded plastic zippers usually cost less than other zippers and can be cut to size and sewn over (though the bulky teeth can bend your needle). They are more durable than nylon zippers and won’t rust like metal zippers, making them ideal for outerwear and outdoor applications. The teeth can pull apart if pressure is applied to the zipper, so they’re not the best choice for luggage.

Metal

Metal zippers have metal teeth that are clamped onto the zipper tape. They are the strongest and most durable zippers and still offer some flexibility. They’re excellent for jeans, bags, and other straight seams. Metal zippers are much heavier than plastic zippers and are too heavy for lightweight fabrics; they also tend to stick more when opening and closing. They can be cut to size, but it usually requires pulling out excess teeth with pliers because attempting to sew directly over the metal teeth will break your needle (and may damage your machine). Finally, metal zippers will rust with prolonged exposure to the elements, so they’re not a good choice for outdoor gear. (P.S. My favorite metal zippers are from Klum House).

Zipper Types

Non-Separating vs. Separating Zippers

Non-separating or closed-end zippers have a bottom stops that keeps the two zipper tapes from fully separating. Non-separating zippers are often referred to as pant, skirt, and dress zippers or bag/handbag zippers. Handbag zippers are more durable than garment zippers. They usually have a wider zipper tape to make insertion easier as well as a larger pull.

Separating or open-end zippers do not have a bottom stop. Instead, they have a retaining box and insertion pin that allow the two zipper tapes to separate and rejoin. Separating zippers are often referred to as jacket zippers.

Invisible/Concealed Zippers

Invisible zippers are a type of nylon coil zippers commonly used for garments. When the zipper is closed, the zipper teeth are fully concealed on the wrong side of the garment. They have small pulls that are meant to inconspicuously nestle within the seam.

Slider Characteristics

Zippers are also described by the type and number of sliders they have and how the sliders are oriented.

Locking sliders will not move unless pulled on and are ideal for garments. Non-locking sliders may move on their own if there is pressure on the zipper.

One-way zippers have a single slider that moves in one direction at a time.

Two-way zippers have two sliders that can be oriented head to head (also called luggage zippers) so the zipper closes when the sliders meet, or tail to tail (also called coverall zippers) so the zipper closes when the sliders are apart.

Reverse zippers have the sliders attached to the wrong side of the zipper.

Reversible zippers have pulls that can be pulled from the front to the back of the slider so the zipper can be operated from either side of the object.

Double zippers have pulls attached to both the right and wrong sides of the slider so the zipper can be operated from either side of the object.

Zipper Sizes

The size (or gauge) of a zipper corresponds to the width of the zipper chain/coil (in millimeters) when the zipper closed. Zipper descriptions will list the closest standard zipper size, so if you measure the zipper yourself you may find a #3 zipper chain is not exactly 3 mm wide. The larger the number, the larger the width of the zipper chain and tape. The size of the zipper is usually marked on the bottom of the slider and (for YKK zippers) will often have abbreviations for the zipper type (e.g., C for coil, V for Vislon, MG for Metal Brass/Gold).

The zipper size you choose for a project should correspond to the weight of the fabric you will sew it to and the scale of the project.

Fabric Weight	Zipper Size	Projects
Light Weight	1–4	skirts, dresses, formal clothing, cushions and pillow cases
	4–4.5	sweet spot for most casual pants
Medium Weight	4.5–5	good for most bag-making applications
	5	my favorite size for jeans
	5–7	jackets, coats, coveralls, bags and luggage
Heavy Weight	8–10	very heavy-duty garments, outdoor applications

Adapted from: Mikayla Keir Zipper Size Chart

Zipper Lengths

The length of a zipper corresponds to the distance between the top and bottom stops, not the length of the zipper tape. Recall that pre-made zippers have about 0.75” of fabric without teeth on either end of the zipper, so the zipper tape is usually about 1.5” longer than the actual zipper length.

Zippers are available in a number of standard lengths, but for some projects you may need to cut a zipper to a custom size. You can: 1) buy a standard size zipper that is longer than you need and trim it to size or 2) buy continuous zippers by the yard.

Trimming a Zipper to Size

Nylon coil and molded plastic zippers can be easily cut with scissors and the teeth/chain can be sewn across with a sewing machine. Cut the excess length from one end of the zipper to preserve one of the stops, then attach a new stop or sew across the zipper teeth to prevent the slider from coming off the other side. To shorten a metal zipper, you will want to pull out excess teeth in the seam allowance with pliers because attempting to sew directly over the metal teeth will break your needle and may damage your machine. If you must sew across a metal zipper, go very slowly and use your hand wheel to precisely place your needle between the metal teeth.

Continuous Zippers (By the Yard)

If you use zippers regularly, it is likely more cost-effective to buy continuous zippers by the yard. Continuous zippers are open-ended: you buy zipper stops and sliders/pulls separately and install them yourself. If you choose to go this route, you will likely want to purchase a pair of pliers, nippers, and a zipper jig to make installation easier.

Sourcing: PDX Sewlarium has a large selection of continuous nylon coil zippers locally. ByAnnie, Wawak, and Sallie Tomato sell continuous zippers online; the latter two also sell nylon coil zippers that look like metal zippers if you like the look of metal but not the hassle of cutting them to size.

Aimee Seaver Pulling Teeth: Tips to Shorten Zippers - Threads

Additional Resources

Video Tutorials from ByAnnie.com Zippers Are EASY!

Kimberly Coffin Anatomy of a Zipper

Mikayla Keir Guide To Zipper Types

Keep In Touch

Thanks very much for reading! If you’d like in-person support and instruction, please sign up for my classes at Modern Domestic or reach out to schedule a private lesson. If you have any questions, feedback, or corrections regarding this post, please don’t hesitate to contact me!