How do I work out how much dirt I will stipulation? It is 70 feet long, I inevitability to raise the echelon...

It is 70 feet long, I inevitability to raise the echelon about 4 - 6 inches, out to approximately 3 foot away from the structure. How much dirt do I need?
Answers:    105 cubic Feet, 70x3x.5, the 6 inches will allow for wastage and compaction
travel to my aunt's house and you'll find all the dirt that you entail.