You can get (7) 2 1/2" strips that are about 21" long. 7 X 16 = 112 strips. Divide 112 in half (because the Jelly roll strips are about 42" long) = 56 strips. So you'll need 1 full jelly roll, plus 14 or 16 extra strips (some jelly rolls have 40 strips and some have 42 strips).