How the conversion works
Volume alone does not tell you how much a material weighs. The conversion requires the material density, which is the weight per unit of volume. Multiply the cubic yardage by the density in tons per cubic yard to get the total weight.
Different materials have very different densities. A cubic yard of gravel weighs roughly 1.4 tons, while a cubic yard of topsoil is closer to 1.1 tons. Using the wrong density can lead to significant ordering errors.
Tons = Cubic yards x Density (tons per cubic yard)
Multiply the volume by the material density to get the weight in tons.