These high quality YKK #3 Nylon Coil Closed-End Zippers are 12 inches or about 30.5 cm long (the full tape, including the fabric at the top and bottom, is about 13.5 inches).
This is a great price for these zippers (just $.80 each), and they won't be restocked.
The zipper tapes are 1 inch (2.5cm) wide. Made in Canada!