Solve for density, mass, or volume from the other two, then see if the material would float or sink in water.
An object floats or sinks in a liquid based on a straightforward comparison: if the object's overall density is lower than the liquid's density, it floats; if higher, it sinks — the same principle (Archimedes' principle) that explains why a solid block of ice floats on water while a similarly sized block of steel does not.
Enter any two of density, mass, and volume, and the calculator solves for the third using the basic relationship density = mass ÷ volume — the same formula rearranged depending on which value you're solving for.
A reference table of common material densities (like water, ice, various metals, woods, and plastics) is included so you can compare your result against familiar materials, or quickly check whether a specific material would float or sink in water without needing to measure a sample yourself.
An object floats in a liquid if its overall density is lower than the liquid's density — that's why ice (0.92 g/cm³) floats on water (1.00 g/cm³), and steel (7.87 g/cm³) sinks unless shaped to displace enough water, like a ship's hull.
For a solid block, only density matters. Hollow shapes (boats, balloons) can float even when made of a denser material, because their average density — including the air or gas inside — is what counts.
Grams, cubic centimetres, and g/cm³ throughout — g/cm³ is numerically identical to kg/L, so you can treat 1 cm³ as 1 mL if that's easier to picture.
