I originally posted this to a thread about mulch, but I don't think too many people saw it because it was an old thread. Here's an area-to-volume calculator that I made using the spreadsheet component from the free office suite, OpenOffice. For those of you who would rather keep Mr. Gates rolling in dough by paying for MS Office, it also works in excel. Click here to get VolumeCalc.xls The loss adjustment is handy when you're using irregular objects which settle after a trip in the dump truck. I use 103% to 105% adjustment for 1.5" river rock, for example - that way I order an additional 3-5%, and it compensates for the settling.