Are you interested in putting the zipper on the outside of the bag or the inside? I think that makes a difference, when I put it on the inside I generally use a 7- 9 inch. On the other hand if I am using it on the outside to close the bag I generally get the zip with 2 pulls or of course you can make your own with the zip by the yard. I actually just bought some from Amazon that was 10 yards and I think there were 15 pulls. I am really excited about the dark zip with the rose gold pull they look awesome.