How to measure zipper length

The theoretical lengths of different zipper types are determined by the length of the fastening chain and the distance between the bottom stop and top stops.

length_zt

ZT

length_zto

ZTO

length_ztx

ZTX

length_bt

BT

length_bto

BTO

length_btx

BTX

The tolerance level:

Theoretical length	Tolerance level
30 -300 mm	± 5mm
301 – 500 mm	± 6mm
501 – 800 mm	± 8 mm
801 – 1500 mm	± 10 mm
1501 – 3000 mm	± 20 mm
3001 –	± 1 %