⚖️Density Calculator
Calculate density, mass, or volume using the formula ρ = m/V. Enter any two values to find the third. Supports 7 density units, 8 volume units, and 7 mass units. Includes a reference table of 20 common material densities.
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Result
8900 kg/m³
Common Material Densities (kg/m³)
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Density Calculator: ρ = m/V — Find Density, Mass, or Volume
Density (ρ) = mass (m) ÷ volume (V). Given any two of these three quantities, the third can be found. Water has a density of 1,000 kg/m³ = 1 g/cm³. Gold: 19,300 kg/m³. Air: 1.225 kg/m³. A material with density greater than water (1 g/cm³) sinks; less than water floats.
Formula: ρ = m/V | m = ρ×V | V = m/ρ
| Material | Density (kg/m³) | Density (g/cm³) |
|---|---|---|
| Water | 1,000 | 1.000 |
| Aluminum | 2,700 | 2.700 |
| Steel | 7,850 | 7.850 |
Density is one of the most important physical properties of a material, used in engineering design, buoyancy calculations, material identification, fluid dynamics, and chemical formulation. Understanding density is essential for calculating shipping weights, concrete volumes, tank capacities, and whether objects float or sink.
Specific Gravity
Specific gravity (SG) is the ratio of a material's density to the density of water at 4°C (1,000 kg/m³). It is dimensionless. A material with SG = 2.7 (aluminum) is 2.7 times denser than water. SG is used in hydrometers to measure battery acid, antifreeze concentration, and alcohol content. Liquids with SG less than 1 float on water (oil, gasoline); those greater than 1 sink.
Frequently Asked Questions
What is the formula for density?
Density ρ = m / V, where m is mass and V is volume. Rearranged: mass m = ρ × V; volume V = m / ρ. The SI unit of density is kg/m³. For many practical purposes, g/cm³ is used: 1 g/cm³ = 1,000 kg/m³. Water has a density of approximately 1 g/cm³ (exactly at 4°C). Example: copper has a density of 8.96 g/cm³. A 1 cm³ cube of copper has a mass of 8.96 g. A 1 m³ cube of copper has a mass of 8,960 kg = 8.96 tonnes.
What is specific gravity and how is it different from density?
Specific gravity (SG) is the ratio of a substance's density to the density of a reference substance, usually water at 4°C (1,000 kg/m³). SG is dimensionless — it has no units. Density has units (kg/m³, g/cm³). For solids and liquids, SG ≈ density in g/cm³ numerically. SG > 1: denser than water, sinks. SG < 1: less dense than water, floats. Examples: ice SG = 0.917 (floats); lead SG = 11.34; gold SG = 19.3. Specific gravity is used in geology, brewing, battery testing, and quality control.
Why does ice float on water if it is the same substance?
Ice (solid water) has a density of approximately 917 kg/m³, while liquid water has a density of 1,000 kg/m³ at 4°C. When water freezes, hydrogen bonds form a crystalline hexagonal structure with more space between molecules than in liquid water, making ice less dense. This is why ice floats — it has a specific gravity of 0.917, meaning about 91.7% of the ice cube is submerged (Archimedes' principle). This unusual property — a solid less dense than its liquid — is vital for life on Earth: ice insulates bodies of water from freezing solid.
How do I convert between density units?
1 g/cm³ = 1,000 kg/m³ = 1 kg/L. To convert lb/ft³ to kg/m³: multiply by 16.018. To convert g/cm³ to lb/in³: multiply by 0.036127. To convert lb/gal (US) to kg/m³: multiply by 119.826. Quick reference: water = 1 g/cm³ = 1,000 kg/m³ = 62.43 lb/ft³ = 8.345 lb/gal. Most engineering problems use kg/m³ (SI) or g/cm³. The US uses lb/ft³ in HVAC and construction, and lb/gal for liquids.