Quick answer

Start by measuring your seam or opening, then match the zipper type to the project's stress and look. For bags and pouches, choose a sturdy metal or polyester zipper with the right length; for garments, consider an invisible zipper for a clean finish. Use a zipper that's slightly longer than the opening if you plan to trim it, but never shorter than needed.

Measure First: How to Determine Zipper Length

Before you shop, measure the seam or opening where the zipper will go. For a centered or lapped zipper, the zipper should be the same length as the opening. For an invisible zipper, you can use a zipper up to 1 inch longer and trim the top after installation. If you're adding a zipper to a bag, measure the top edge of the bag, including seam allowances, and subtract the seam allowance to find the finished opening length.

When a project calls for a specific length, you can often buy a longer zipper and shorten it from the top. This works well with nylon coil zippers, but metal zippers are harder to shorten because the bottom stop is fixed. If you're using a metal zipper, buy the exact length or adjust your pattern to fit the zipper you have.

Match Zipper Type to Your Project

The three most common zipper types are coil (nylon), polyester, and metal. Coil zippers are flexible and great for curved seams and lightweight garments. Polyester zippers are durable and resist rust, making them a good choice for bags and outdoor gear. Metal zippers offer a vintage look and strong hold, but they can snag delicate fabrics and are heavier.

For bags and pouches, a metal or polyester zipper with a sturdy pull is often best. The Metal Zipper & Hardware for the Wristlet includes a 9" YKK® metal closed bottom zipper with a donut-style pull, plus a snap hook, D-ring, and leather cord—everything you need to finish a small bag with a professional look. For quilts, a longer coil or polyester zipper is easier to sew through layers and less likely to break.

Consider Zipper Hardware and Pulls

The zipper pull isn't just about looks—it affects how easy the zipper is to grip. Large pulls, like donut or ring styles, are easier for kids and people with limited dexterity. For bags, a D-ring or snap hook can double as a strap attachment, saving you from buying extra hardware separately.

If your project needs extra hardware, look for a kit that bundles the zipper with matching pieces. The Strap & Hardware Kit for the Crosscut Sewing Messenger Bag Pattern includes 60" of 35mm polyester webbing, two 1 1/2" rectangle rings, and a sliding buckle. This kit pairs with the pattern to give you everything for the strap, so you only need to choose the zipper separately.

Decision Rules for Zipper Selection

  • Rule 1: Measure the opening, then add seam allowances: Always measure the finished opening length, not the fabric edge. For bags, subtract seam allowance from the top edge. For garments, measure the seam line where the zipper will sit. Write down the measurement before you shop.
  • Rule 2: Choose the zipper type by fabric and stress: Coil zippers for curved seams and lightweight fabric; polyester for durability and water resistance; metal for a classic look and heavy-duty use on bags. If in doubt, choose polyester for bags and coil for garments.
  • Rule 3: Buy longer if you can trim, but not for metal: Coil and polyester zippers can be shortened from the top. Metal zippers have a fixed bottom stop, so buy the exact length or adjust the pattern. For metal zippers, match the length precisely.
  • Rule 4: Match the pull to the user and use: Large pulls like donut or ring styles are easier to grip and work well for bags. Small pulls are fine for hidden zippers in garments. Think about who will use the item and how often.

Zipper and Hardware Kits That Simplify Your Project

  • Metal Zipper & Hardware for the Wristlet: This kit includes a 9" YKK® brand metal closed bottom #4.5mm zipper with metal teeth and a donut style pull, plus a snap hook, D-ring, leather cord, and sew-on label. For a small wristlet or pouch, this kit gives you a sturdy metal zipper and the hardware to attach a strap or key chain. The donut pull is easy to grip, and the metal teeth hold up to daily use.
  • Strap & Hardware Kit for the Crosscut Sewing Messenger Bag Pattern: The kit includes 60" of 35mm polyester webbing, two 1 1/2" rectangle rings, and one 1 1/2" sliding buckle, designed for the Crosscut Sewing Messenger Bag Pattern. If you're making a messenger bag, this kit provides the strap hardware so you can focus on choosing the right zipper for the bag body. The webbing is wide enough for comfortable carry, and the buckles let you adjust the length.

Which Zipper Fits Your Project?

Best for

  • Sewing a small bag or wristlet: a metal zipper kit with hardware
  • Making a messenger bag: a strap hardware kit plus a separate zipper matched to the bag opening

Not for

  • Garments needing a concealed closure: choose an invisible zipper instead of a metal or chunky hardware kit