If you're pouring a concrete foundation, how do you figure out how much concrete you'll need? There's a pretty simple formula. Take the length in feet times the width and height of the wall to figure your cubic footage. Then divide that figure by 27 to get your cubic yards (because there are 27 cubic feet in a cubic yard). Most cement trucks hold between eight and 14 cubic yards. An average house with a full foundation will take four truckloads.
For more on cement, consider:
9 Easy DIY Concrete Projects
Radio: DIY Concrete
Concrete and Cement: A Case of Mistaken Identities