How to Measure a Lap Zipper

When you go to buy a zipper, you will notice they come in different lengths. This length actually only measures the distance from the zipper pull (the plastic or metal tab you pull to open or close the zipper) to the zipper stop (the metal or plastic bracket at the bottom of the teeth). The zipper tape, or fabric that the zipper teeth are attached to, extends an extra 3/4 inch or so at the top and bottom. Lap zipper installations often use a zipper that’s one to two inches longer than the opening in the garment. This allows the zipper pull to stick up above the garment and out of the way while you’re stitching, since sewing around it can make the stitches look uneven.Here is how to measure a lap zipper.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• Measuring tape
• Garment
• Sewing machine (optional)
• Thread (optional)
• Scissors (optional)

How to Measure for a Lap Zipper

1. Sew the garment fabric, including the seams around the opening, as usual.

2. Lay the garment flat and smooth out any wrinkles.

3. Measure the distance from the bottom of the opening to the top edge of the garment. For example, a zipper opening in the back of a dress may measure 18 to 21 inches, while the opening in the side of a skirt may be 9 to 12 inches.

4. Buy a zipper that’s at least as long as this measurement. For example, an 18-inch opening needs at least an 18 inch zipper.

5. To avoid stitching near the zipper pull, buy a zipper one to two inches longer than this measurement.

How to Shorten a Lap Zipper

6. After sewing the zipper to the garment, open the zipper by pulling the zipper tab down.

7. Stitch back and forth a few times across one side of the zipper teeth, zipper tape and seam allowance where you want the zipper to end. Do not stitch through to the outside of the garment.

8. Repeat Step 2 for the other side of the zipper.

9. Cut the zipper just above the stitching.

10. Finish the upper edge of the garment with a facing, collar or waistband.

Tips & Warnings

• It’s better to buy a zipper that is too long than one that is too short. You can easily shorten a long zipper, but a zipper that is too short may make it difficult to change into and out of the garment.
• You can find inexpensive measuring tapes made specifically for sewing in many fabric stores. These flexible measuring tapes are about 5 feet long, and often come marked in inches on one side and centimeters on the other.