The basic method: centered zipper on a seam
A centered zipper is the most common type and the easiest to start with. The zipper sits in the middle of a seam, with fabric on both sides. You sew the seam closed first, then open it up and stitch the zipper underneath so it's hidden when the garment is worn.
Start by sewing the seam where the zipper will go, using a regular stitch length. Sew all the way across—do not leave a gap yet. Press the seam open flat with an iron. Mark where the zipper will start and stop with a pencil or fabric pen on the wrong side of the fabric. Most zippers go from the top of the seam down about 6 to 8 inches, but check your pattern.
Use a seam ripper to carefully cut and remove the stitches between your two marks. You now have an opening with the seam allowances folded to either side. This is where the zipper will sit.
Key Takeaways
- A centered zipper is sewn underneath a seam so it's hidden; you sew the seam first, then rip out the stitches where the zipper goes.
- Pin the zipper face-down on the seam allowance, with the teeth sitting right at the fold of the fabric, before you stitch it down.
- A zipper foot—a special presser foot that lets you stitch close to the teeth—is nearly essential and costs $5 to $15.
- Stitch down one side of the zipper, then flip the garment over and stitch the other side so both sides are even and the zipper lies flat.
- If the zipper puckers or pulls, you stitched too close to the teeth or pulled the fabric too tight as you sewed.
Preparing the zipper and fabric
Place the zipper face-down on the seam allowance of one side of your opening. The metal or plastic teeth should sit right at the fold where the fabric bends. Pin it in place along the length of the zipper, using pins perpendicular to the teeth so they won't get in your way when you sew.
If you are using a machine, switch to a zipper foot. This is a narrow presser foot that lets you stitch very close to the zipper teeth without hitting them. Most machines come with one, or you can buy a universal zipper foot for $5 to $15. If you are sewing by hand, you do not need a special foot—just use a needle and thread.
Before you start stitching, close the zipper slider (the pull tab) and move it away from where you will be sewing. You do not want to stitch over the slider itself.
Stitching the first side of the zipper
Using a machine with the zipper foot, stitch along the length of the zipper, staying about 1/8 inch away from the teeth. Sew from the top of the zipper down to the bottom. Your stitches should go through the zipper tape (the flat woven part) and the seam allowance underneath, but not through the main fabric of the garment.
If you are sewing by hand, use a backstitch—the strongest hand stitch for this job. Bring the needle up through the fabric, then push it back down a short distance behind where it came up, and bring it up again a short distance ahead. This creates a solid line of stitches. Space them about 1/8 inch apart.
Stop stitching about 1 inch before the bottom of the zipper. This gives you room to pivot and stitch across the bottom later if your pattern calls for it. Remove the pins as you go.
Stitching the second side of the zipper
Flip the garment over so you are looking at the other side of the seam. Fold back the fabric to expose the other side of the zipper tape. Pin the zipper tape to the seam allowance on this side, making sure the zipper is centered and not twisted.
Stitch this side the same way you stitched the first side—about 1/8 inch from the teeth, using the zipper foot or backstitch. Start at the top and work your way down. This time, try to match the line of stitching on the first side so both sides look even. If the lines are slightly different, the zipper will still work, but it will look more professional if they match.
When you reach the bottom, you can stitch across the bottom of the zipper tape if your pattern shows this. Some patterns do; some do not. Check before you finish.
Removing the basting stitches and testing the zipper
Once both sides are stitched, use a seam ripper to remove the original seam stitches that are still visible on the right side of the fabric. Work carefully so you do not cut the zipper tape or your new stitches. Pull out the thread pieces with tweezers.
Close the zipper slider all the way up and all the way down a few times. It should move smoothly without catching or pulling the fabric. If it catches, you may have stitched too close to the teeth on one side. If the fabric puckers, you may have pulled it too tight as you sewed, or the zipper tape is not sitting flat underneath.
Press the finished zipper from the wrong side with an iron on a low setting. Do not press directly on the zipper slider—move it out of the way first.
Exposed zippers: when the zipper shows on the outside
An exposed zipper (also called a separating zipper) sits on top of the fabric instead of hidden underneath. This is common on jackets, hoodies, and bags. The zipper is visible from the outside, so it becomes part of the design.
Sew the seam where the zipper will go, then press it open. Place the zipper face-up on top of the seam allowances, with the teeth centered over the seam. Pin it in place. Using the zipper foot, stitch along both sides of the zipper tape, about 1/4 inch away from the teeth. Both lines of stitching will be visible on the outside, so keep them straight and even.
Exposed zippers are actually easier than centered zippers because you do not have to hide them—if your stitching is a little crooked, it is part of the look. They are a good choice if you are new to sewing zippers.
Common problems and how to fix them
If the zipper puckers or the fabric bunches up around it, the most common cause is pulling the fabric too tight as you sew. Let the fabric feed naturally under the presser foot without pushing or pulling. If you are sewing by hand, do not pull the thread so tight that it gathers the fabric.
If the zipper slider catches or sticks, the zipper tape may not be lying flat. Use a seam ripper to open up a few stitches, flatten the tape, and re-stitch. Alternatively, the zipper itself may be damaged—try a different zipper to see if the problem goes away.
If one side of the zipper is crooked or does not line up with the other side, you can carefully rip out the stitches and re-sew. Use a seam ripper to cut the thread every few stitches, then pull the thread out. This takes patience but is worth it if the zipper looks off-center.
If you stitched through the main fabric by accident and the stitches show on the right side, you can carefully rip them out and re-sew, staying closer to the fold of the seam allowance. A small mistake usually is not noticeable once the garment is worn.
Frequently Asked Questions
Can I sew a zipper by hand instead of using a machine?
Yes. Use a backstitch, which is the strongest hand stitch for zippers. Space your stitches about 1/8 inch apart and keep them as straight as possible. Hand-sewn zippers take longer but work just as well. Many people hand-sew zippers on delicate fabrics or repairs because they have more control.
What size zipper do I need?
Zippers are measured by the length of the metal or plastic teeth, not including the slider. A pattern will tell you the length you need—usually 7 inches, 9 inches, or 14 inches. Buy a zipper that is the same length or slightly longer; you can always trim the excess tape at the bottom. Do not buy one that is shorter than your pattern calls for.
Do I need a special zipper foot?
A zipper foot makes the job much easier because it lets you stitch very close to the teeth without hitting them. Most machines come with one. If yours did not, a universal zipper foot costs $5 to $15 and works on almost any machine. You can sew a zipper without one, but you will have to stitch farther away from the teeth, which looks less neat.
What if the zipper is too long for the opening?
Trim the excess zipper tape at the bottom with scissors or a seam ripper, leaving about 1/2 inch of tape below where the opening ends. You can also sew a small bar of stitches across the zipper tape to stop the slider from sliding off the bottom. Do not cut the metal or plastic teeth themselves—only the tape.
How do I fix a zipper that separates or splits while I am wearing it?
If the slider has come off the bottom, you may be able to slide it back on. If the teeth are bent or broken, the zipper is damaged and needs to be replaced. Rip out the old stitches with a seam ripper and sew in a new zipper using the same method.