Density, Mass & Volume Calculator

Understanding the density calculator — concept and principle

Density tells you how much mass is packed into a given volume. It identifies materials, predicts whether something floats, converts between mass and volume for shipping or recipes, and checks purity. This calculator takes mass and volume and returns density in kg/m³ and g/cm³, plus specific gravity relative to water.

Same volume, 2.7 times the mass of water — density 2,700 kg/m³.

How it is calculated

Density: ρ = m ÷ V. With mass in kg and volume in litres, ρ (kg/m³) = m ÷ (V ÷ 1,000), because 1 m³ = 1,000 L.
g/cm³: numerically equal to kg/L, so ρ (g/cm³) = m ÷ V with m in kg and V in L. 1 g/cm³ = 1,000 kg/m³.
Specific gravity: SG = ρ ÷ 998 kg/m³. This calculator uses 998 kg/m³, close to the density of pure water at about 20 °C.

Rearranged, m = ρV and V = m ÷ ρ.

The principle

Density is an intensive property: it does not depend on how much of the substance you have. A teaspoon and a bucket of the same water have the same density. It reflects how heavy the atoms or molecules are and how tightly they are packed. Metals with heavy atoms in close-packed crystals, such as lead or gold, are dense; foams and gases with lots of empty space are not.

Specific gravity removes units by comparing with water. A value above 1 means the material sinks in water, below 1 means it floats, provided it is solid and not hollow.

Worked example

Inputs: m = 2.7 kg, V = 1 L.
ρ = 2.7 ÷ (1 ÷ 1,000) = 2.7 ÷ 0.001 = 2,700 kg/m³.
In g/cm³: 2.7 ÷ 1 = 2.7 g/cm³.
SG = 2,700 ÷ 998 ≈ 2.705410822.

Each point is the calculator re-run with only “Volume (L)” changed; the gold point is the default example. Change the inputs above and this chart follows your numbers.

Volume (L)	Density (kg/m³)
0.25	10,800
0.5	5,400
0.75	3,600
1	2,700
1.25	2,160
1.5	1,800
2	1,350

How to read the result

2,700 kg/m³ is the density of aluminium. Some reference values: fresh water about 1,000 kg/m³, seawater about 1,025, steel about 7,850, gold about 19,300, air at sea level about 1.2. Liquids and gases change density with temperature, and gases also with pressure, so compare values measured under similar conditions.

Common mistakes

Confusing litres with cubic metres; 1 L is 0.001 m³.
Using bulk volume for powders or grains, which includes air gaps and gives a lower "bulk density".
Comparing specific gravities that use different water references (4 °C vs 20 °C), which differ by about 0.2%.

Keep in mind: Results are only as accurate as the volume measurement. Irregular objects should be measured by water displacement, porous materials can absorb water, and temperature changes the density of liquids, so treat the result as an estimate unless measured carefully.

Frequently asked questions

How do I measure the volume of an irregular object?

Submerge it in a measuring container of water and read how much the level rises; that rise is the object's volume (Archimedes' method).

Is specific gravity the same as density in g/cm³?

Almost, because water is about 1 g/cm³. Strictly SG is dimensionless and depends on the reference temperature.

Why is ice less dense than water?

Hydrogen bonds hold ice in an open crystal, so ice is about 917 kg/m³ and floats on liquid water.

Sources: BIPM, The International System of Units (SI Brochure), 9th edition · CRC Handbook of Chemistry and Physics (densities of elements and water)

Checked 8 Nov 2026. Standard textbook formulas in SI units, computed in your browser. For learning and estimates — real designs must follow your local codes and be checked by a qualified engineer.

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