Cubic yards to tons?

I have some very big piles/rows of dirt/compost. I need to find out how many tons I have. What would to calculation for this be?
If I take the L x W x H that would give me the volume or cubic feet, yes?
Then what?
Help please.
If I take the L x W x H that would give me the volume or cubic feet, yes?
Then what?
Help please.