Relative Density Calculator: Compare Substance Densities Easily

Relative density compares your substance’s density to a reference such as water (1000 kg/m³ at 4 °C) (NIST, 2023). Enter both values, pick kg/m³ or g/cm³, press “Calculate,” and the tool returns a unit-less ratio that tells you instantly whether the material is lighter or heavier than the reference.