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Fly front zipper - how to make it

Edited to add: I've made a pdf file for this instruction. You can download this here.

Regularly I read that constructing a fly front zipper in a pair of pants is something that is considered difficult. It's not. There's a very good method by Sandra Betzina that can be found on the Taunton site.
Until my last pair of pants I used that method, but have now blended that method together with two other methods I found (one in Threads and one in Ottobre magazine). The advantage for me is that the facing of the fly is in this method from the start and that the front is not sewn together first, but only pinned.
I really recommend using a facing to prevent damage to your undergarments, but if you want, you can omit it from this. I use a zipper that is longer than needed, this is what I really like about Sandra Betzina's method, as you don't have to bother with the zipper stop, and it gives a very finished look when the waistband is added.

The pictures are made with a scrap of fabric, non matching zipper and thread.

1. Mark the center front by basting, add a fusible interfacing to the right (overlapping) side (picture shows wrong side)

2. Press the left side almost 1 cm (5/8 inch) from the center front (picture right side)

3. Stitch from start of zipper to inside seam, but leave enough room to stitch the inside seam of the pants later.

4. Stitch the zipper to the facing on the right corner to secure the zipper.

5. Stitch the zipper with facing to the left part of the pants, close to the zipper
This secures both zipper and facing to the pants.
Don't go down to the very end, leave a bit of space to fold away the facing later for the topstitching. I did it right by accident when writing this, but later did this part wrong and ended up taking out a few stitches.

6. Press the overlapping side on the center front line.
Pin it to the left side, matching center front.

7. Turn to the other side, pin the zipper to the fly extension, do NOT pin the fabric on the front

8. Stitch the zipper on the extention, again NOT the front.

10. Fold away the facing and topstitch on the front of the pants (sorry, I did not use a guide or template, this is a bit wider at the bottom, but you see what I mean)

The inside, I could have made the facing a bit shorter.

Important: do not cut off the extra length of the zipper until you have sewed the waistband. I did this once, and ended up starting all over again!

Edited to add these pictures, I realised that I forgot to make a tack on the bottom part (as often seen in RTW). This tack fastens the facing.

On the inside I added an extra tack to secure the facing (and yes, the facing is shortened too).


  1. So far I have avoided pants with fly front zippers! That is one thing I really want to learn before the end of the year so I'm bookmarking your very helpful tutorial.

  2. Thank you for such a great tutorial on the front fly zipper. You make it seem so easy to do.
    Happy Stitching!

  3. Great tutorial, Sigrid, I think I will try it on my next pair of pants!

  4. What a great tutorial! I've got a pair of pants on the pile and will definitely refer back to your fabulous instructions. Thank-you!

  5. Beautiful tutorial - with clear pictures! Thank you!

  6. Okay, okay. I'm going to try it again. I'm bookmarking this too.

  7. Thank you so much Sigrid. This was such a great and easy way to do it, wonderful tutorial.

  8. A nice try to make this not so scary to sewers. However, the fly shield(facing in this instance) shows the zipper being stitched to the curved edge instead of the straight edge. It is easier to apply the zipper to the straight edge of the shield which will line up better with the garment straight edge at CF and when finished will overlap the topstitched area with a matching shape that should be slightly bigger than the topstitched facing to completely cover the zipper.

  9. Wonderful information on how to make it. Highly detailed and quite great recommendations. Many thanks


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