Hi, Sophie (maker) here :) Honestly, I didn’t know exactly how much I’d need. Last time I made one, by the time I got to the last knot I had barely enough so knotting became a slower process at that point. This time I wanted to make sure I had more than enough. Also, I knew longer pieces of excess cord could be used for other smaller projects (keychains, earrings, tassels). Regardless of the project, if there’s at least 6 inches of excess cord, I keep it in color coordinated bags.