Density Calculator – Mass, Volume & Density
Calculate density, mass, or volume using the formula density = mass/volume.
What is Density?
Density is the mass per unit volume of a substance: ρ = m/V (density = mass / volume). It is an intrinsic property — it does not depend on how much of the substance you have. A small gold nugget and a gold bar have the same density (19,320 kg/m³), though vastly different masses.
Density determines whether objects float or sink (objects less dense than water float), how materials behave under pressure, and is fundamental to chemistry, engineering, and physics.
Common Material Densities
For reference (in g/cm³): Water: 1.00; Ice: 0.92 (why ice floats); Aluminum: 2.70; Iron: 7.87; Copper: 8.96; Lead: 11.34; Gold: 19.32; Air: 0.0012; Wood (oak): ~0.75; Concrete: ~2.30; Human body: ~0.99 (slightly less than water, explaining why we can float).
These values are at standard conditions (20°C, 1 atm). Most materials expand slightly with temperature, reducing density as temperature rises.
How Density is Used
Buoyancy: Objects with density less than the fluid they are placed in will float. A steel ship floats because the hull is hollow — the average density of the ship including air is less than water. Material identification: Calculating the density of an unknown sample and comparing it to known values can identify the material. Quality control: Density measurements detect voids, inclusions, and composition variations in manufactured parts.
Frequently Asked Questions
Why does ice float on water?
Ice has a density of about 0.917 g/cm³ — less than liquid water at 1.00 g/cm³. This unusual property occurs because ice forms a crystalline hexagonal lattice structure with more space between molecules than liquid water. Almost all other substances are denser in solid form than liquid.
What is specific gravity?
Specific gravity is the ratio of a substance's density to the density of water. Since water = 1.00 g/cm³, specific gravity is numerically equal to density in g/cm³. A specific gravity greater than 1 means the substance sinks in water; less than 1 means it floats.
How do you measure the density of an irregular object?
Use the water displacement method (Archimedes' principle): submerge the object in a graduated cylinder of water and measure the volume of water displaced. That equals the object's volume. Combine with mass measurement (scale) to calculate density.