Cubic meters, which measure volume, are converted to tons, which measure mass, by multiplying the number of cubic meters of a substance by its density in units of cubic meters per ton. Density is a physical property defined as the mass of a substance per unit volume.

Common density units include kilograms per cubic meter, grams per milliliter and pounds per cubic foot. It is unlikely that a density measurement is given in cubic meters per ton, so the density may need to be converted into the proper units. The type of tons must be known before converting. Short or U.S. tons are commonly used within the United States, while metric tons are used elsewhere. Density in kilograms per cubic meter is divided by 1,000 to convert to metric tons per cubic meter, and it is divided by 907.18 to convert to U.S. or short tons per cubic meter. Density in grams per milliliter is numerically equivalent to density in metric tons per cubic meter, and it is multiplied by 1.10 to convert to short tons per cubic meter. Density in pounds per cubic foot is multiplied by 0.016 to convert to metric tons per cubic meter, and it is multiplied by 0.018 to convert to short tons per cubic meter.