Sheshovel, I just noticed that in your example you didn’t convert your mulch depth over (one way or another) to feet, rather than inches. Your 9 yards of mulch would be way too much for an area of 10’ x 8’ (80 s.f.).
Instead of multiplying feet by inches 10’ x 8’ x3” lets go with common units, therefore 10’ x 8’ x .25’ or 20 cubic feet. Now convert the 20 cubic feet to cubic yards by dividing by 27 (20 / 27 = .74 cubic yards). So, one yard will do for this small area.
