Density Calculator
Calculate density from mass and volume.
How this calculator works
Density measures how much mass is packed into a given volume — a fundamental property used to identify and compare materials.
Result shown in both kg/m³ and g/cm³ (equivalent to g/mL).
Using density to identify materials
Density is often used as a quick way to identify or verify a material, since each substance has a characteristic density under standard conditions — gold, for example, is notably denser than most metals, which is part of why density testing is used to help detect counterfeits.
Density also determines whether an object floats or sinks in a given fluid — anything less dense than the fluid it's placed in will float, which is the basic principle behind buoyancy calculations in physics and engineering.
A worked example
An object with a mass of 2.7kg and a volume of 0.001 cubic meters (1 liter): density equals 2,700 kg per cubic meter, or 2.7 g/cm3 — close to the density of aluminum, a common reference point.
Compare that to an object of the same mass but 0.003 cubic meters volume (3 liters): density drops to 900 kg per cubic meter, or 0.9 g/cm3 — less dense than water, meaning this object would float.
Using density to identify materials
Density is often used as a quick way to identify or verify a material — gold, for example, has a distinctive density around 19.3 g/cm³, far higher than most metals, which is part of why density testing is a classic method for detecting counterfeits.
In everyday contexts, density explains why some objects float and others sink: anything less dense than water (about 1 g/cm³) floats, while anything denser sinks, regardless of the object's size or weight alone.
Frequently asked questions
How does this compare to water's density?
Water has a density of about 1 g/cm³ (1000 kg/m³) — materials denser than that sink in water, and less dense materials float.
Why do objects with the same mass sometimes have different density?
Density depends on volume as well as mass — two objects can weigh the same but have very different densities if one is more compact (smaller volume) than the other.
How is density related to whether something floats?
An object floats in a fluid if its density is less than the fluid's density — this is why wood floats in water (lower density) while most metals sink (higher density).
Why do some heavy objects float while some light objects sink?
Floating depends on density (mass relative to volume), not weight alone — a large object can be lightweight for its size (low density, floats) while a small object can be extremely dense (sinks) despite weighing less overall.