Zipper-phobia is real (especially for newbie sewers) and the fly front zipper is no exception. But it doesn’t deserve its bad boy reputation. In fact, it’s actually one of the easiest to sew because most of the construction is hidden from view. Whether you’re sewing one into a pair of custom jeans or fresh dress pants, here’s how to sew a fly front zipper — promise it’s easier than you think.
Fly Front Zipper
What You Need
Pro Tip: Purchase a standard zipper that’s longer than what’s called for in the pattern. We recommend going with one that measures 1-2″ longer than the zipper opening, as it allows you to avoid sewing close to the zipper tab mechanism.
1. Apply Interfacing
Cut two pieces of fusible interfacing that will cover both sides of the zipper flaps. The interfacing should extend from the center front to the flap edge. Press or fuse the interfacing to the underside of the zipper flaps.
2. Stitch the Interfacing
Using a ⅝” seam allowance, stitch the two pant fronts together. Using a regular length stitch, start stitching midway into the crotch curve and stop at the base of the zipper, then backstitch. Use a basting stitch to continue stitching along the center.
Good to Know: You start midway into the crotch curve so the inseams and crotch seams can be stitched in the right sequence.
3. Cut and Press
Use scissors to clip into the seam allowance at the base of the curve, stopping right before the stitch line. Press the flap seam open.
4. Pin the Zipper
With the front-facing sides of the pant fronts facing each other, and the left side of the zipper flap lying flat, lay the zipper upside down along the center front seam as shown above. The bottom of the zipper should be positioned at the base of the curve.
5. Stitch the Zipper
Using a zipper foot, stitch the zipper in place close to the zipper teeth. Turn the zipper over so the front of the zipper is revealed. Stitch the zipper again ⅛” from the fold. This stitch will show when the zipper is opened, so it should be done neatly.
6. Flip and Pin
Flip the pant fronts so the underside of the zipper faces up and the pant fronts face each other. Lay the zipper flat onto the free zipper flap; allow the zipper to fall into place naturally. Then pin the unstitched side of the zipper in place.
Stitch the zipper to this flap anywhere within the zipper leg.
Turn the pants to the front-facing side. The zipper should lie flat on the work surface. Mark where the zipper ends with a pin. Then use chalk or a marking pen to mark the final stitching line 1¼” from the center front seam.
Also mark the bottom curve, making sure to avoid the zipper base.
9. Finishing Stitches
Following the marked line, sew the final stitching line. Undo the center front basted seam from step 3.
And there you have it — a beautifully sewn fly front zipper!
There needs to be a final photograph of the completed zipper–both open and zipped.