Density Mass Volume
Calculator

Density is mass per unit volume, telling you how tightly matter is packed into a given space, measured in kilograms per cubic meter in SI units (though grams per cubic centimeter is common for everyday materials). It's a way of comparing how 'heavy for their size' different materials are, independent of how much of the material you have.

Density is an intensive property, meaning it doesn't depend on the amount of substance present — both mass and volume scale up together for a bigger chunk of identical material, so their ratio (density) stays constant. This is different from mass or volume alone, which are extensive properties that do depend on quantity.

An object floats in a fluid if its overall density is less than the fluid's density, and sinks if it's greater, because buoyant force (related to the fluid's density and the object's submerged volume) must be able to counteract the object's weight. This is why a solid steel block sinks in water but a steel ship, with mostly air-filled hollow space, floats — the ship's average density across its whole hull volume is lower than water's.

Density typically varies with temperature and pressure, since most materials expand (becoming less dense) when heated and contract (becoming denser) when cooled, and gases are especially sensitive to pressure changes. Reference tables usually specify the exact temperature and pressure conditions the listed density applies to, and using the calculator's result outside those conditions introduces some error.

Because density is a distinctive intensive property, measuring an object's mass and volume and calculating density lets you compare the result against known reference values for common materials (gold, aluminum, various woods, plastics) to narrow down or confirm what it's made of. This is a classic technique, famously associated with Archimedes verifying whether a crown was pure gold.