How to Sew Convertible (Zip-off) Pants: Tutorial

For by DH and me, zip-off pants fall into the category of “better than sliced bread”.  They offer an option to pack one less item when traveling and are great for day trips, especially during the fall when there are weather changes.  Then there’s the “petite” issue.  Rarely have I been fortunate enough find them in a size that doesn’t require alterations.   For Kevin, zip-off’s are easy to find but the configuration of pockets just hasn’t matched his preferences.   You know where this is going…..

Now that I have much more time to sew, I set off to make a pair of Kevin (shorts) and one pair (capris) for me.  After scouring the internet for a tutorial, I ended up purchasing out of print Kwik-Sew 2406 from an Etsy seller.  There may be other patterns available however I’ll save you the trouble.  All  you really need is a pants pattern and this tutorial.  


1. Pants pattern and fabric

2. Decide on where you want the zipper to fall on the pants.  i.e. above the knee, at the knee or below.

3.  Notions – snaps, additional zippers or cord.

4. Zippers – purchase one for the fly and 2 light to mid-weight separating zippers for the legs.  I used a 27″ zipper for Kevin’s knee-length pants but would reduce that to 26″ the next time.  For my capri-length pants I used a 18.5″ zipper.  Note:  Purchase zippers at the exact length if you can, or you can purchase a longer zipper than you need and reduce the size by removing and replacing the zipper stop.  Archer Zippers in NYC will cut zippers to your desired length – you will need to call them.  Their color palate is amazing.


1.  Start with a pants pattern that fits well and which has fairly straight or wide legs.  Avoid fitted pants.

2.  Cut the pants from the pattern, cutting the upper legs 2″ longer than the desired length of the upper pant leg.  Note:  To accommodate the tapering of the sides when you turn up the hem, remember to cut an outward flare on the hem seam allowance.

  • In addition to the pattern pieces, you will need 2 strips of fabric for the zipper guards.  Cut them the length of the zipper by 2-1/2″ wide (cut on the grain)
  • Do not cut the lower legs at this time. (but do make sure you have enough fabric left for the lower leg pieces).

3.  Sew the pants.  Stop before finishing the hem.

4.  Overcast the hem edge.

5.  Turn the 1-7/8 hem to the inside and pin in place. (If you started with a 2″ hem, you likely lost 1/8″ when overcasting the edge.)

Zipper Application: 

Note:  If you need to cut your zipper, do not cut it until after you have completed the next step.

1.  Pin the zipper to the hem with the right side of the zipper facing the hem.

The zipper start and end:

  • Should be at the inseam – zipping the pant legs is too difficult if the start is on the outside seam.
  • Should barely meet. The zipper will not work if there is an overlap, but it is OK if you have a small gap between the start and the end.   Note:  Zippers will zip in opposite directions, as in the following photo.
Zippers pinned to the hem, going in opposite directions.

2. From the back side of the zipper, stitch the zipper to the upper leg, approximately 1″ from the bottom of the hem.

2.   You’re getting there.  Now you will stop sewing and cut the lower leg pieces from your remaining fabric.

Cutting the Lower Pants:

1. I would recommend that you make a pattern.  Measure at the line where you sewed the zipper to the hem of the upper leg, you need the top of the lower pants to be the exact circumference as this measurement. 

2.  Following the same taper as the upper leg, cut the lower leg pieces, adding 1″ to the top of each lower leg piece.

Making a pattern for the lower leg. Click to enlarge.

3.  Sew the sides of the legs together.

4.  To reduce the chance of making an error, mark the inseam and outer seam with your favorite marking tool.

5. Turn under 1/2″ at the top of each lower leg.  Pin or press in place.

6. Now pin the wrong side of the top edge of the lower leg to the right side of the zipper.

Pinning the lower leg to the zipper

7.  Carefully unzip the zipper.  Toss the pants aside for a few minutes.

8.  Check the pins to make sure the zipper is in place.  Folded edge of the lower leg should be close to the zipper teeth.

9.  Working from the right side, sew the lower leg to the zipper.

10.  Zip the lower to the upper leg to assure that it looks correct and to take pride in what you’ve done!

11.  Repeat with the other leg.

12.  Remove both lower legs in preparation for sewing the zipper guard.

Zipper Guard

You could probably stop at this point however all of the zip-off pants I’ve seen have a zipper guard on the inside.  I’m thinking this is for comfort.  It’s the last step and a fairly easy one, so pull out the two  2-1/2 by zipper length pieces of fabric.

1.  Check the zipper guard length against the zipper length to confirm that it is the same length.  If not, adjust.

2.  Fold the zipper guard in half lengthwise and overcast the edges.

Zipper guard

3.  Turn pants inside-out (remember, lower pants are removed).

4.  Pin the zipper guard to the inside of the zipper.  Cover the zipper and check to be sure that it is at least 1/4″ from the hemline (so it doesn’t show when wearing with the lower legs zipped off).  The zipper guard should meet at the ends rather than overlapping (creates bulk).

5. Turn pants right side out.  Removing pins as you go, sew 1/8″ from the zipper stitching line (the one you sewing back when you sewed the zipper into the pants).  You will sew through all layers of the fabric and the zipper.

Sewing the Zipper guard
Finished zip-off pants

My Capri Zip-off’s

I’d love to hear if this works for you.  What is missing in the tutorial?