Density Calculator
Find density, mass or volume using ρ = m / V, with results in g/cm³, kg/m³ and lb/ft³.
Reviewed by the WorldCalcs team · Methodology · Last reviewed: July 2026
Density
2 g/cm³
Density
2 000 kg/m³
Density
124.8559 lb/ft³
ρ = m / V
What is density?
Density tells you how much mass is packed into a given amount of space. A dense material feels heavy for its size; a light material feels airy. Formally, density is mass divided by volume, written with the Greek letter rho: ρ = m / V. Two objects can be the same size but have very different densities — a block of iron and a block of foam of equal volume weigh wildly different amounts because iron packs far more mass into each cubic centimetre.
The density formula
The three quantities are linked by one simple relationship, so if you know any two you can find the third:
- Density: ρ = m / V
- Mass: m = ρ × V
- Volume: V = m / ρ
The SI unit of density is kilograms per cubic metre (kg/m³), but grams per cubic centimetre (g/cm³) is common in everyday use and chemistry. They convert cleanly: 1 g/cm³ = 1000 kg/m³. In imperial units you'll often see pounds per cubic foot (lb/ft³), where 1 g/cm³ ≈ 62.428 lb/ft³.
Worked example
Suppose a metal sample has a mass of 200 g and a volume of 100 cm³. Divide mass by volume: 200 ÷ 100 = 2.0 g/cm³. That's the same as 2000 kg/m³, or about 124.8559 lb/ft³. Because its density is roughly twice that of water (1.0 g/cm³), a solid piece of this metal would sink.
Common densities (for reference)
These are approximate textbook values at everyday conditions:
- Air (sea level): ~0.0012 g/cm³ (1.2 kg/m³)
- Ice: ~0.917 g/cm³ (917 kg/m³)
- Water: 1.0 g/cm³ (1000 kg/m³)
- Aluminium: ~2.70 g/cm³ (2700 kg/m³)
- Iron: ~7.87 g/cm³ (7870 kg/m³)
- Gold: ~19.3 g/cm³ (19 300 kg/m³)
Anything less dense than the fluid it sits in will float; anything denser will sink. That's why ice floats on water and a gold ring drops straight to the bottom. Weight itself comes from mass and gravity — see Newton's second law for that step, or explore more tools on Math Calculators.
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Results are estimates and may contain errors — for general information only, not professional advice. Always verify before relying on them. Disclaimer
How to use
Pick what you want to find, enter the two known values with their units, and the calculator applies ρ = m / V and rearrangements to solve for the third.
Density results are shown in all three common units — g/cm³, kg/m³ and lb/ft³ — so you can drop the answer straight into whichever context you're working in.