wikiHow Millimeters to Grams Calculator Millimeters (mm) and grams (g) are units of measurement for different physical quantities. Millimeters measure length or distance, while grams measure mass or weight. Therefore, it is not possible to directly convert millimeters to grams. However, if you know the material density and the volume of the material in millimeters, you can use the following formula to convert millimeters to grams: mass (g) = volume (mm³) x density (g/mm³) For example, if you have a block of aluminum with dimensions of 10 mm x 10 mm x 10 mm, and the density of aluminum is 2.7 g/mm³, then you can calculate the mass of the block as follows: volume = 10 mm x 10 mm x 10 mm = 1000 mm³ mass = 1000 mm³ x 2.7 g/mm³ = 2700 g Therefore, the mass of the aluminum block is 2700 grams. Page