I used 100' of white and 100' of red, I used 3' of each color for each bracelet with about 4 to 5 inches of scrap of each color on each bracelet. So I could have went a little shorter on the cord used but I just stayed with 3' for ease. I guessed with the size. I found a website that showed how to make a 7 1/2" bracelet , so once I made one I had my daughter try on the size and it was a good fit so I just kept making them that size. I did some in 8" for larger kids and adults just in case. I chose 8" because it fit my wrist. In all it took around 8 hours to do I guess I received the cord in the mail Thursday night and worked on them for a couple hours, then worked on them the next day and was done by 2pm, I also delt with kids, dinner, baths , ect So it could have been done in less time. I did have issues in the beginning with melting the cord together, once I changed lighters they melted fine. The other lighter kept making the melted spot black.
Here is the website I used
http://theworldaccordingto*******bl...wToMakeTwoColorCobraKnotParacordBracelet.html
I used paracordplanet.com used a promo code they had on facebook and spent $23 for all materials, so not bad considering they are selling for $5 each.