convert cubic yards of run to tons travaux godart. Convert cubic feet to cubic yards by dividing by 27 the number of cubic feet in one cubic yard. for instance, if you need 135 cubic feet of rocks, dividing 135 cubic feet by 27 gives you 5 cubic yards. step 5. convert cubic yards to tons of rock. for most gravel and small rock, there are about 1 and 38 tons 2750 pounds per cubic yard .