I apparently CANNOT do math. I am trying to wind off warp long enough to make 3 rugs in a row. I started with light blue that I bought and grey that came with the loom. I used the entire spool of blue and had to replace it with some light green. Then I ran out of grey and was stuck. I ordered some that matches as closely as possible (and another green, just in case) and then had to wait for a week. FINALLY got it in the mail, used up both spools of grey and still had a TON more to do! All in all, I used 1 light blue spool, 2 light greens, 1 grey, 2 more similar greys, and a huge pile of really thick grey that doesn't match at all... These rugs are going to be insane and I need to quadruple check my numbers from now on.
Oh, and I still have to go to a yarn store and find some that matches one of those colors for the beginning and ends of the rugs- BECAUSE I HAVE NONE LEFT!
All in all, I used around 2,333 yards of yarn- give or take.