Well sunshine, I think you will also need the depth. Picture this: You have this walkway that the dog keeps tearing up by digging. It's 18 feet of walkway long, and it's 9 feet wide. So you could say this is 162 square feet (when you multiply 9*18--because width times length equals square feet), but stone has depth also, right? So you will have to know how deep the stone layer will be to get your right answer. When you know that, you can figure cubic feet/yards/meters by multiplying depth times width times length.

Shout if you get to that place and need help.

Shout if you get to that place and need help.