Determining the thickness of the string you need is critical, but it is also important to figure out how many feet of string you’ll need to restring your vertical blind or traverse rod.
When restringing vertical blinds and traverse rods, the formula used to estimate the length of string you will need is:
2 x Width + Height = Total Amount Needed
The string is one long piece. Both ends tie off inside the head rail of the track.
This video shows how to restring a standard vertical blind. Your blind may look different or stack differently.