Density Calculator — ρ = m/V
Calculate density, mass, or volume using ρ = m/V. Includes material density table, buoyancy basics, unit conversions, and practical applications.
Density explains why a steel ship floats and a steel ball sinks, why oil sits on top of vinegar in salad dressing, and why you feel lighter in water. It's mass packed into space — and the ratio of the two determines whether something rises, sinks, or floats in a given medium.
The CalcHub density calculator solves for density, mass, or volume — whichever you need.
The Formula
ρ = m / V- ρ (rho) = density (kg/m³ or g/cm³)
- m = mass (kg or g)
- V = volume (m³ or cm³)
Common Material Densities
| Material | Density (g/cm³) |
|---|---|
| Air (at sea level) | 0.0012 |
| Water | 1.00 |
| Seawater | 1.025 |
| Aluminum | 2.70 |
| Steel | 7.87 |
| Lead | 11.34 |
| Gold | 19.30 |
| Osmium (densest element) | 22.59 |
How to Use the Calculator
- Find density: enter mass and volume
- Find mass: enter density and volume
- Find volume: enter density and mass
Worked Example
A metal sample has a mass of 158.7 g and a volume of 20.2 cm³. What material might it be?
ρ = 158.7 / 20.2 = 7.86 g/cm³
That matches steel almost exactly. This is actually how material identification works in practice — archaeologists, geologists, and materials scientists use density testing as a quick non-destructive check.
How do I find the volume of an irregular object?
Displacement! Lower the object into a measuring cylinder of water and read how much the water level rises. This is Archimedes' method — still the simplest way to measure irregular volumes. The volume equals the water displaced.
Why does density change with temperature?
Most materials expand when heated, increasing volume while mass stays the same, so density decreases. Water is famously anomalous — it's densest at 4°C and expands when cooling below that, which is why ice floats and lakes freeze from the top down.
What's specific gravity?
Specific gravity is density relative to water: SG = ρ_material / ρ_water. Since water is 1 g/cm³, specific gravity equals density numerically in g/cm³ units. It's dimensionless and commonly used in brewing, urine analysis, and gemology.