Density Calculator
Solve for density, mass, or volume from any two known values. Get the result in g/cm³, kg/m³ and lb/ft³, plus specific gravity and a sink-or-float verdict. Build volume from box dimensions if you only know the shape, and compare your result against a table of common materials.
Formula
Worked example
100 g in 50 cm³: ρ = 100 ÷ 50 = 2 g/cm³ (2,000 kg/m³, about 125 lb/ft³), twice as dense as water, so it sinks. To reverse it: a 50 cm³ part at 2 g/cm³ weighs 2 × 50 = 100 g.
How the Calculation Works
Density is defined as mass divided by volume and represents how much matter is packed into a given space. This calculator uses that single physical definition and reports the result in two standard units simultaneously, g/cm³, which is convenient for everyday lab work, and kg/m³, the SI unit used in engineering and science. Because 1 g/cm³ equals exactly 1000 kg/m³, converting between them is trivial and the calculator handles it for you.
How to Use This Calculator
Enter the mass of your object or sample in grams and its volume in cubic centimetres, then read off the density. You can measure mass with a balance scale and volume either directly (for regular geometric shapes) or by water displacement for irregular solids, the Archimedes principle approach. Make sure both measurements use consistent units before entering them, since mixing unit systems is the most common source of error.
What the Density Value Tells You
Water at 4 °C has a density of 1.00 g/cm³ (1000 kg/m³), which makes it the practical reference point for everyday buoyancy judgements. Any material with a density above 1 g/cm³, such as steel at roughly 7.8 g/cm³ or concrete at around 2.3 g/cm³, will sink in fresh water. Materials below that threshold, like most woods (0.4-0.9 g/cm³) or ice (0.917 g/cm³), float. Seawater is slightly denser than fresh water at about 1.025 g/cm³, so the exact sinking or floating threshold shifts a little in marine contexts.
Limitations and Edge Cases
This calculator assumes a uniform, homogeneous material, that is, density is the same throughout the sample. For composite objects, a porous material like foam, or a hollow container, the result reflects average bulk density, not the density of the solid material itself. Temperature also matters: most materials expand slightly when heated, increasing volume and lowering density, so measurements made at very different temperatures are not directly comparable. Gases and liquids are especially sensitive to temperature and pressure, and their densities should be looked up at specified conditions rather than assumed constant.
Density of common materials
| Material | g/cm³ | kg/m³ | Sinks or floats in water |
|---|---|---|---|
| Balsa wood | 0.160 | 160 | Floats |
| Cork | 0.240 | 240 | Floats |
| Pine wood | 0.500 | 500 | Floats |
| Ice | 0.917 | 917 | Floats |
| Water (4 °C) | 1.000 | 1,000 | Neutral |
| Seawater | 1.025 | 1,025 | Sinks |
| Concrete | 2.300 | 2,300 | Sinks |
| Aluminium | 2.700 | 2,700 | Sinks |
| Glass | 2.500 | 2,500 | Sinks |
| Iron / steel | 7.870 | 7,870 | Sinks |
| Copper | 8.960 | 8,960 | Sinks |
| Silver | 10.490 | 10,490 | Sinks |
| Lead | 11.340 | 11,340 | Sinks |
| Mercury | 13.530 | 13,530 | Sinks |
| Gold | 19.320 | 19,320 | Sinks |
Approximate values at room temperature. Use these in the reverse modes to solve for mass or volume.
Frequently asked questions
What is the density of water in g/cm³?
Pure water reaches its maximum density of 1.000 g/cm³ at 4 °C (39.2 °F). At room temperature (around 25 °C) it drops slightly to about 0.997 g/cm³, but 1 g/cm³ is the standard reference value used in most practical calculations.
Why does ice float on water if it is made of water?
When liquid water freezes, it forms a hexagonal crystal lattice that is less tightly packed than liquid water. Ice has a density of approximately 0.917 g/cm³, which is lower than liquid water, so it floats. This is an unusual property, most substances are denser in their solid state than in their liquid state.
What units should I use when measuring density?
In scientific and laboratory contexts, density is most commonly expressed in g/cm³ (equivalent to g/mL for liquids) or in the SI unit kg/m³. Engineering applications often use kg/m³. For this calculator, enter mass in grams and volume in cubic centimetres to get g/cm³ directly.