Sewing a zipper into a coat is a machine-sewing task that takes about an hour once you have the right foot
You will need a zipper foot — a presser foot that lets the needle run close to the zipper teeth on both sides. Most machines come with one, or you can buy a universal zipper foot for $8 to $15. The zipper itself should be 2 inches longer than the opening you are closing. A coat zipper is usually a heavy-duty separating zipper (one that splits completely at the bottom), sized 24 to 30 inches for an adult coat.
The basic method is: pin the zipper face-down along one side of the opening, sew it down with the zipper foot, flip the coat right-side out, then repeat on the other side. The whole process takes longer to prepare than to stitch. Most mistakes happen because the zipper is pinned crooked or the needle hits the zipper teeth instead of the tape.
Key Takeaways
- A zipper foot lets your needle run close to the zipper teeth; without one, you will sew too far from the teeth and the zipper will be stiff.
- Pin the zipper face-down on the wrong side of the fabric, with the zipper tape aligned to the raw edge of the opening.
- Sew with the zipper foot, keeping the needle 1/8 inch away from the teeth on your first pass, then stitch the other side the same way.
- Test the zipper before you trim the excess length; if it catches, you may have sewn too close to the teeth.
- Trim the zipper tape above the top stop after both sides are sewn, then fold the coat facing or binding over the zipper tape to hide it.
Prepare the coat opening and zipper
Lay the coat flat with the wrong side facing up. The opening where the zipper will go should have raw edges that are even and straight. If you are replacing a broken zipper, remove the old one by cutting the stitches with a seam ripper or small scissors and pulling it out. Press the opening flat with an iron to remove wrinkles and old stitch marks.
Measure the opening from top to bottom. Your zipper should be at least 2 inches longer — if the opening is 24 inches, use a 26-inch zipper. Lay the zipper next to the opening and check that the pull tab will sit at a comfortable height when the coat is buttoned or worn. On a coat, the pull tab usually ends up at chest height.
If the zipper is new and stiff, run it up and down a few times by hand to loosen it. This takes 30 seconds and prevents the pull from jamming later.
Pin the zipper to the first side
Lay the zipper face-down (teeth facing the fabric) along the right side of the opening, with the zipper tape aligned to the raw edge. The top stop of the zipper should sit about 1/2 inch below the top of the opening. Use straight pins or clips to hold it in place every 2 to 3 inches. The zipper should lie flat and straight — any twists or bunches now will show when you sew.
Check that the zipper tape is not folded under itself and that the teeth are visible and not hidden by fabric. A common mistake is pinning the zipper too far from the edge; the tape should touch the raw edge of the opening, not sit 1/4 inch away from it.
Sew the zipper foot to the first side
Install the zipper foot on your machine. Most zipper feet have a small screw or lever that lets you move the needle position left or right so it runs close to the teeth. Adjust it so the needle will be about 1/8 inch away from the zipper teeth — close enough that the stitching holds the tape, but far enough that the needle does not hit the metal or plastic teeth.
Thread the machine and lower the presser foot. Start sewing at the bottom of the zipper, using a straight stitch and a stitch length of 2.5 to 3 mm (a normal length). Sew slowly and keep the edge of the zipper foot aligned with the zipper tape. Stop and raise the presser foot if you need to adjust the fabric or check your line. When you reach the top, backstitch to lock the thread and cut it.
Remove the pins and flip the coat right-side out. The zipper should now be attached to one side of the opening, with the teeth facing outward and the tape hidden on the wrong side.
Sew the zipper to the second side
Lay the coat flat again with the wrong side up. Fold the other side of the opening so the raw edge aligns with the zipper tape on the opposite side. Pin it in place the same way you pinned the first side — every 2 to 3 inches, with the tape touching the raw edge.
Sew this side the same way: zipper foot installed, needle 1/8 inch from the teeth, slow speed, straight stitch. Start at the bottom and sew to the top, backstitching at the end. When both sides are sewn, the zipper should be sandwiched between the two layers of the coat opening, with the teeth running down the middle.
Close the zipper by hand to check that it moves smoothly. If it catches or feels stiff, you may have sewn too close to the teeth. If the zipper is very stiff, you can carefully trim a tiny bit of fabric from the edge with scissors, but do this only if the stitching is not in the way.
Trim and finish the zipper ends
Once both sides are sewn and the zipper works smoothly, trim the excess zipper tape above the top stop. Leave about 1/2 inch of tape above the stop, then cut straight across with scissors or a rotary cutter. This prevents the long tail from getting caught in the coat or showing at the neckline.
If the coat has a facing (a strip of fabric sewn to the inside of the opening) or binding (a folded strip that wraps the edge), fold it over the zipper tape now and stitch it down by hand or machine. This hides the zipper tape and gives the inside of the coat a finished look. If the coat does not have a facing, you can fold the raw edge of the opening inward 1/4 inch and stitch it down to cover the zipper tape.
Common mistakes and how to avoid them
The most common error is sewing too far from the zipper teeth because you are not using a zipper foot. Without one, the regular presser foot keeps the needle too far away, and the zipper tape does not get held down properly. The result is a zipper that pulls away from the fabric or feels loose. Always use a zipper foot.
Another frequent mistake is pinning the zipper crooked so it twists as you sew. Spend an extra minute checking that the zipper lies flat and straight before you start sewing. If you notice it is crooked halfway through, stop, remove the stitches with a seam ripper, and start again.
Hitting the zipper teeth with the needle breaks the needle and can damage the zipper. Prevent this by setting the needle position so it is clearly away from the teeth — 1/8 inch is a safe distance. If you hear a click or feel resistance as you sew, stop when ready and check the needle position.
Sewing the zipper too tight (too close to the teeth) makes it hard to move the pull tab. If this happens after both sides are sewn, you can carefully trim a thin strip of fabric from the edge with a seam ripper or small scissors, but this is tedious. It is easier to get the distance right the first time.
Frequently Asked Questions
Do I need a special zipper for a coat?
A coat zipper is usually a separating zipper, meaning it splits completely at the bottom so you can open and close the coat fully. Regular zippers do not separate. Coat zippers are also heavier-duty than dress zippers. Check the zipper package to confirm it says "separating" or "coat zipper" before you buy.
What if my zipper is too short for the opening?
If the zipper is shorter than the opening, you have two options: buy a longer zipper and start over, or close the top of the opening with a button or snap and use a shorter zipper for the rest. The second option works if the opening is only slightly too long. Measure carefully before you sew.
Can I sew a zipper by hand instead of with a machine?
Yes, but it takes much longer — usually 2 to 3 hours instead of 30 minutes. Use a backstitch and thread that matches the coat. A machine stitch is stronger and more even, so it is worth using a machine if you have access to one.
How do I fix a zipper that gets stuck after I sew it in?
First, try running the pull tab up and down slowly a few times to loosen it. If that does not work, rub a graphite pencil along the zipper teeth (not the fabric) to lubricate them. If the zipper is still stuck, you may have sewn too close to the teeth and need to trim the fabric edge slightly with a seam ripper.
What stitch length should I use?
Use a stitch length of 2.5 to 3 mm, which is a normal length for most sewing. This is short enough to hold the zipper tape securely but long enough that you can remove the stitches later if you need to. Avoid very short stitches (under 2 mm) because they are hard to remove if something goes wrong.