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I'm doing pattern https://www.friendship-bracelets.net/pattern.php?id=1(Basic Candy Stripe) but I want to know how much floss i should cut for a 7 inch wrist. I'm also going to loop the thread do a knot at the top and a three inch braid at the bottom to tie together. Every tutorial I'm seeing is suggesting a different length. Any help is greatly appreciated. :)

It depends on how tight you knot, what string you are using, how long you want you bracelet, what pattern you use, etc.
That's why it's difficult to give an estimation. The best way is to knot some bracelets yourself and write down how much string you used. You can calculate for future bracelets from there.
I always advice 120-130 per string. That's (more than) enough is most cases.

That is 120 cm = 47 in. (almost 4 feet). Because you will be using a loop at one end, each physical piece of string will need to be twice this length because each end will be used as a separate pattern string.
I usually use about 41 in (104 cm) per string, but it is better to be a little too long than too short.