If you want to fill it full 8x8x1 is 16 cubic feet of sand. A cubic yard is 27 cubic feet so 1/2 yard should be good.

8x8x1= 64 cubic feet

64 cubic feet= 2.37 cubic yards

Assuming all measurements are accurate; 2.37 cubic yds would fill the sandbox to the brim. If you ordered 2 cubic yds, the sandbox would be filled up approx 10.12 inches.

Wylie is correct. I don't how I came up with that figure. 8x8=64. back to 2nd grade I guess.