Density Calculator
Solve for density (ρ), mass (m), or volume (V) using the formula ρ = m / V. Select the variable you want to find, enter the other two, and click Calculate.
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Common Material Densities
Click any row to load those density values into the calculator above.
| Material | Density (g/cm³) | Density (kg/m³) |
|---|
Understanding Density
Density is a fundamental physical property that expresses how much mass is packed into a given volume. The formula is simple:
ρ = m / V
where ρ (rho) is density, m is mass, and V is volume. Rearranged: m = ρ × V (to find mass) and V = m / ρ (to find volume).
Why Density Matters
Density determines whether an object floats or sinks in a fluid. An object floats if its density is less than that of the surrounding fluid. Ice (≈ 0.917 g/cm³) floats on water (1.0 g/cm³); a steel ball (≈ 7.8 g/cm³) sinks. This principle — Archimedes' principle — is foundational in fluid mechanics.
Density is also important in material science, engineering (selecting materials by weight-to-strength ratios), geology (identifying minerals), and chemistry. For gas-phase density problems, see our Ideal Gas Law Calculator, which can solve for molar density at a given pressure and temperature.
Unit Conversions
The SI unit of density is kg/m³, but g/cm³ and g/mL are commonly used in chemistry because 1 g/cm³ = 1 g/mL = 1000 kg/m³. Water at 4 °C has a density of exactly 1 g/cm³ (or 1000 kg/m³), making it a convenient reference point.
Frequently Asked Questions
What is the density of water?
Pure water has a maximum density of 1.000 g/cm³ (1000 kg/m³) at 4 °C. At room temperature (25 °C), it is approximately 0.997 g/cm³. Saltwater is denser (~1.025 g/cm³ for ocean water), which is why objects float more easily in the ocean than in fresh water.
Is density the same as specific gravity?
Specific gravity (relative density) is the ratio of a substance's density to that of a reference substance — usually water at 4 °C. Since water's density is 1 g/cm³, the specific gravity of a substance is numerically equal to its density in g/cm³, but specific gravity is dimensionless. For example, gold's density is 19.3 g/cm³, so its specific gravity is 19.3.
How do I measure the volume of an irregular solid?
Use water displacement (Archimedes' method): fill a graduated cylinder with a known volume of water, submerge the solid, and measure the new water level. The difference is the volume of the solid. Multiply by the density of water (1 g/cm³) if you want the mass instead, or divide the solid's mass by this volume to get density.
Does temperature affect density?
Yes. Most materials expand when heated, increasing volume and decreasing density. Water is a notable exception — it is densest at 4 °C and expands both when heated above and when cooled below that temperature (which is why ice floats). Gases are highly affected by temperature; at higher temperatures, gas density drops significantly.
