Density, the relationship between an object's mass and volume, is a fundamental property in physics, chemistry, engineering, and materials science, used to identify substances and calculate other properties. This density calculator solves for density, mass, or volume using the formula density = mass ÷ volume, depending on which two values you know. It's useful for students conducting science experiments, engineers calculating material properties, or anyone needing to determine whether an object will float (lower density than the fluid) or sink (higher density). Common applications include calculating the density of liquids, solids, or comparing materials for engineering projects.