Zippers: How to measure a zipper length. How to measure a zipper for size.

How do you measure a zipper? A zipper is basically measured by the length of the zipper coil or from top metal stoppers (that prevent zipper slider from coming off the zipper) to bottom metal stopper (or retainer box for separating zippers). The overall zipper length is usually about 1-1.5 inches more for seam allowance.

The zipper in the photo is a 7 inch zipper with overall length of 8.5 inches.