Density, Mass and Volume

Written byOleh Soloninupdated 5 October 2026

Solve for

Material

Mass

Mass unit

Volume

Volume unit

Density unit

Result

Result1,000
What was calculatedDensity, kg/m³
Workingρ = m ÷ V = 1,000 kg ÷ 1 m³ = 1,000 kg/m³
Density, kg/m³1,000
Density, g/cm³1
In waterthe same density as water
Relative to water1
Materiala custom value

One formula in three shapes

The density formula ρ = m ÷ V in all three shapes: density, mass or volume from the other two, in grams, kilograms, tonnes, cubic centimetres, litres and cubic metres, with the working and g/cm³ converted to kg/m³.

Density is mass divided by volume: ρ = m ÷ V. The same formula gives mass, m = ρ × V, and volume, V = m ÷ ρ. A block of 78 g taking up 10 cm³ has a density of 7.8 g/cm³, or 7,800 kg/m³.

Units are where problems go wrong. The calculator takes mass in grams, kilograms or tonnes, volume in cm³, litres or m³, and density in kg/m³ or g/cm³, and converts between them itself.

How to use

Choose what to find: density, mass or volume.
Enter the two known quantities and pick their units, grams and cubic centimetres for a school problem, say. For mass or volume you can take the density from the list of materials.
Read the answer in your units, the working on one line, and the density in both kg/m³ and g/cm³.

The density, mass and volume formulas

ρ = m ÷ V for density, m = ρ × V for mass, V = m ÷ ρ for volume. Put the quantities into matching units first: grams with cubic centimetres give g/cm³, kilograms with cubic metres give kg/m³.

Density: 78 g ÷ 10 cm³ = 7.8 g/cm³. Mass: 1,000 kg/m³ × 0.002 m³ = 2 kg, the weight of 2 litres of a substance at 1,000 kg/m³. Volume: 540 g ÷ 2.7 g/cm³ = 200 cm³.

From the definitions of the SI units: a litre is a cubic decimetre.
Quantity	Conversion
1 g/cm³	= 1,000 kg/m³
1 kg/m³	= 0.001 g/cm³
1 l	= 1 dm³ = 1,000 cm³ = 0.001 m³
1 m³	= 1,000 l = 1,000,000 cm³
1 t	= 1,000 kg = 1,000,000 g

Float or sink

The ratio of a substance's density to that of water is its relative density. Below one, a solid object made of it floats in water; above one, it sinks. The calculator shows the ratio and a note for every calculation.

Relative density equals the density in g/cm³ numerically, because water is taken here as 1,000 kg/m³, which is 1 g/cm³.

What this calculator shows

Density, mass or volume from the other two
The working on one line, with units
Density in both kg/m³ and g/cm³
The ratio to water and whether a solid object floats

What to keep in mind

Water is taken as 1,000 kg/m³.
Densities in the materials list are approximate room-temperature values; a real sample can differ, especially wood, concrete and fuel.

FAQs

How do I find density?

Divide mass by volume: ρ = m ÷ V. 78 g ÷ 10 cm³ = 7.8 g/cm³.

How do I find mass from density and volume?

Multiply density by volume: m = ρ × V. For example, 2.7 g/cm³ × 200 cm³ = 540 g.

How do I find volume from mass and density?

Divide mass by density: V = m ÷ ρ. 540 g ÷ 2.7 g/cm³ = 200 cm³.

How do I convert g/cm³ to kg/m³?

Multiply by 1,000: 7.8 g/cm³ = 7,800 kg/m³. Divide by 1,000 to go back.

What is relative density?

The ratio of a substance's density to water's. It has no unit and equals the density in grams per cubic centimetre numerically.

How do kg/m³ and g/cm³ relate?

By a factor of a thousand: 1,000 kg/m³ is 1 g/cm³, the density of water. That is why relative density against water matches the figure in g/cm³.

What floats and what sinks?

Anything denser than water's 1,000 kg/m³ sinks. Ice at 917 kg/m³ floats; iron at 7,870 does not.

Worked example

A block from a school problem

Input: Mass 78 g, volume 10 cm³

Output: Density 7.8 g/cm³, which is 7,800 kg/m³

Note: ρ = m ÷ V = 78 g ÷ 10 cm³. It is denser than water, so the block sinks.

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