Some rock installation companies charge by the cubic yard and others charge by the hour. It generally takes 1 person 1 hour to install 1 cubic yard of rock. Hourly rates tend to be $50 – $70 per hour per laborer. So if, for example, you need 10 cubic yards of rock spread, then it’ll probably cost between $550 – $650. As for calculations
, 1 cubic yard = 1.15 tons and 1 cubic yard = 27 square feet.