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Density Converter: Convert kg/m³, g/cm³, lb/ft³, kg/L and More

Density is one of the most useful properties for identifying and comparing materials. It tells you how much mass is contained within a given volume and is used in physics, chemistry, engineering, construction, manufacturing, petroleum, geophysics, and material science.

The most common SI unit of density is kilograms per cubic meter (kg/m³). However, depending on the application, density may also be expressed in grams per cubic centimeter (g/cm³), grams per liter (g/L), kilograms per liter (kg/L), pounds per cubic foot (lb/ft³), pounds per cubic inch (lb/in³), pounds per gallon (lb/gal), slugs per cubic foot (slug/ft³), and other units.

Switching between these units manually can be inconvenient because both mass and volume units have to be converted correctly. A small mistake in either part can produce a completely wrong density value.

The CalculatorKits Density Converter makes this process easier. Enter a density value, select the unit you have, choose the unit you need, and the converted result appears instantly.

The current CalculatorKits tool supports 25 density units and uses kg/m³ as its base unit for conversions.

What Is Density?

Density describes the amount of mass contained in a certain volume.

The standard formula is:

ρ = m/V

where:

ρ = density

m = mass

V = volume

For example, if an object has a mass of 10 kg and occupies a volume of 2 m³:

ρ = 10/2

ρ = 5 kg/m³

So the density of the object is 5 kg/m³.

Density is therefore a ratio between mass and volume. A material with more mass packed into the same amount of space has a higher density.

The SI coherent derived unit for density is kilogram per cubic metre (kg/m³). BIPM lists density or mass density as kg m⁻³ in its SI documentation.

What Is a Density Converter?

A Density Converter is an online tool that changes a density measurement from one unit to another without changing the physical quantity.

For example:

1000 kg/m³ = 1 g/cm³

and:

1 g/cm³ ≈ 62.428 lb/ft³

These values describe the same density using different measurement systems.

Density conversion can become particularly useful when comparing technical specifications from different countries or industries. Scientific data may use g/cm³, engineering documentation may use kg/m³, and American construction or industrial specifications may use lb/ft³.

The CalculatorKits converter uses kg/m³ as its base unit and converts the input to the selected target unit using the corresponding conversion factors.

How to Use the Density Converter

Using the CalculatorKits Density Converter requires only a few steps.

1. Enter the density value.
2. Select the unit you are converting from.
3. Select the unit you want to convert to.
4. View the converted result instantly.
5. Use the result in your calculation or technical work.

For example, to convert 1000 kg/m³ to g/cm³, enter 1000, select kg/m³ as the input unit, and select g/cm³ as the output unit.

The result is:

1000 kg/m³ = 1 g/cm³

The converter also provides common conversion presets such as kg/m³ to g/cm³, g/cm³ to kg/m³, kg/m³ to lb/ft³, lb/ft³ to kg/m³, g/L to kg/m³, and kg/m³ to g/L.

Density Conversion Formula

Density conversion is based on the same physical quantity expressed using different units.

CalculatorKits uses this general conversion approach:

Result = (Input × From Factor) ÷ To Factor

The tool first relates the input unit to its base unit, kg/m³, and then converts the base value into the selected target unit.

For a simple example:

1 kg/m³ = 1000 g/m³

Therefore:

5 kg/m³ = 5000 g/m³

The conversion factor depends on both the mass unit and the volume unit.

Why Is kg/m³ the Standard Density Unit?

The SI system uses the kilogram as the base unit of mass and the metre as the base unit of length. Because volume is expressed as cubic metres, density naturally becomes kilograms per cubic metre.

BIPM identifies the kilogram as the SI unit of mass and the metre as the SI unit of length. SI derived units are formed from combinations of SI base units.

Therefore:

Density = mass/volume

becomes:

kg/m³

This makes kg/m³ the natural reference unit for many scientific and engineering calculations.

kg/m³ to g/cm³

One of the most common density conversions is between kilograms per cubic metre and grams per cubic centimetre.

The relationship is:

1 g/cm³ = 1000 kg/m³

Therefore:

1 kg/m³ = 0.001 g/cm³

The conversion formulas are:

g/cm³ = kg/m³ ÷ 1000

and:

kg/m³ = g/cm³ × 1000

Example

Convert 2700 kg/m³ to g/cm³.

2700 ÷ 1000 = 2.7 g/cm³

Therefore:

2700 kg/m³ = 2.7 g/cm³

This is a useful value when discussing materials such as granite or other dense solids.

g/cm³ to kg/m³

To convert g/cm³ to kg/m³:

kg/m³ = g/cm³ × 1000

For example:

2.7 g/cm³ × 1000 = 2700 kg/m³

Therefore:

2.7 g/cm³ = 2700 kg/m³

This conversion is particularly common in material science because g/cm³ is frequently used for material density while engineering calculations often use kg/m³.

NIST lists the exact relationship:

1 g/cm³ = 1000 kg/m³.

kg/m³ to g/L

Another useful conversion is between kilograms per cubic metre and grams per liter.

Because:

1 m³ = 1000 L

and:

1 kg = 1000 g

the numerical values are equal:

1 kg/m³ = 1 g/L

Therefore:

1000 kg/m³ = 1000 g/L

This is especially convenient when working with liquids.

For example:

850 kg/m³ = 850 g/L

This type of conversion can be useful for oils, fuels, and other liquids.

CalculatorKits specifically includes kg/m³ to g/L among its common conversion presets.

kg/L and kg/m³

The relationship between kilograms per liter and kilograms per cubic metre is:

1 kg/L = 1000 kg/m³

Therefore:

1 kg/m³ = 0.001 kg/L

For example:

850 kg/m³ = 0.85 kg/L

This is another convenient way to express the density of liquids.

kg/m³ to lb/ft³

Pounds per cubic foot is a common density unit in US customary and engineering applications.

The conversion is approximately:

1 kg/m³ = 0.062428 lb/ft³

Therefore:

1 lb/ft³ ≈ 16.0185 kg/m³

NIST gives the relationship between pound per cubic foot and kilogram per cubic metre as approximately 16.01846 kg/m³ per lb/ft³.

Example

Convert 1000 kg/m³ to lb/ft³.

1000 × 0.062428 ≈ 62.428 lb/ft³

Therefore:

1000 kg/m³ ≈ 62.428 lb/ft³

This is why water’s density is commonly given as approximately 62.4 lb/ft³ in imperial engineering contexts.

lb/ft³ to kg/m³

The reverse conversion is:

kg/m³ = lb/ft³ × 16.0185

For example:

50 lb/ft³ × 16.0185 ≈ 800.925 kg/m³

Therefore:

50 lb/ft³ ≈ 800.93 kg/m³

This conversion is useful when working with US engineering specifications and converting them into SI units.

kg/m³ to lb/gal

Pounds per gallon can also be used to describe density, particularly in petroleum and fluid related applications.

CalculatorKits includes lb/gal among its supported density units and distinguishes it as a US gallon based unit in its unit comparison.

The conversion is approximately:

1 kg/m³ = 0.0083454 lb/gal (US)

Therefore:

1 lb/gal (US) ≈ 119.826 kg/m³

NIST lists the US pound per gallon relationship as approximately 119.8264 kg/m³.

Example

Convert 1000 kg/m³ to US lb/gal.

1000 × 0.0083454 ≈ 8.3454 lb/gal

Therefore:

1000 kg/m³ ≈ 8.345 lb/gal (US)

This is an important conversion because US and Imperial gallons are not the same volume.

Density and the Difference Between US and Imperial Gallons

When converting density using gallons, always check which gallon is being used.

A US gallon and an Imperial gallon have different volumes.

As a result, a density expressed in lb/gal will produce different values depending on the gallon definition.

This is particularly important for petroleum, fuel, chemicals, and fluid engineering.

NIST provides separate conversion factors for pound per gallon using US gallons and Canadian or UK Imperial gallons.

If the source specification does not clearly identify the gallon type, do not assume the two units are interchangeable.

Density in g/L

Grams per liter is commonly used for liquids and solutions.

The useful relationship is:

1 g/L = 1 kg/m³

Therefore:

500 g/L = 500 kg/m³

and:

1000 g/L = 1000 kg/m³

This makes g/L particularly convenient for many laboratory and chemistry calculations.

For example, an oil with a density of:

850 kg/m³

can also be expressed as:

850 g/L

and:

0.85 kg/L

Density in lb/in³

Pounds per cubic inch is a much larger density unit numerically because a cubic inch is a very small volume.

NIST gives:

1 lb/in³ ≈ 27,679.9 kg/m³.

Therefore, a material with a density of 7,870 kg/m³ has a density of approximately:

0.2843 lb/in³

This unit may appear in material specifications and engineering documentation, particularly when dimensions are given in inches and mass is measured in pounds.

Density in slug/ft³

The slug is a unit of mass used in the British engineering system.

Density can therefore be expressed as:

slug/ft³

NIST gives:

1 slug/ft³ ≈ 515.379 kg/m³.

This unit is less common in everyday calculations but can appear in aerospace and engineering contexts.

The presence of units such as slug/ft³ makes a multi-unit density converter useful when working across different engineering unit systems.

Common Density Conversion Table

Density	Equivalent
1 kg/m³	0.001 g/cm³
1 kg/m³	1 g/L
1 kg/m³	0.001 kg/L
1 kg/m³	0.062428 lb/ft³
1 g/cm³	1000 kg/m³
1 g/cm³	1000 g/L
1 g/cm³	1 kg/L
1 g/cm³	62.428 lb/ft³
1 lb/ft³	16.0185 kg/m³
1 lb/in³	27,679.9 kg/m³
1 slug/ft³	515.379 kg/m³
1 lb/gal US	119.826 kg/m³

The exact conversion factors used for the imperial units should be kept at full precision during calculations and rounded only for final presentation. NIST provides the corresponding conversion factors for these density units.

Real World Density Examples

Density becomes much easier to understand when you see how it applies to familiar materials.

Water

A commonly used reference value for water is approximately:

1000 kg/m³

which is equivalent to:

1 g/cm³

and:

1000 g/L

CalculatorKits uses this relationship as one of its real world examples.

Oil

CalculatorKits gives an example density of approximately:

850 kg/m³

which is:

0.85 g/cm³

This illustrates why oil generally has a lower density than water.

Granite

CalculatorKits uses:

2700 kg/m³

for granite, equivalent to:

2.7 g/cm³.

Wood

The tool gives an oak example of approximately:

600 kg/m³

which corresponds to approximately:

37.45 lb/ft³.

Metal

CalculatorKits provides a metal example of:

7870 kg/m³

which is approximately:

491.3 lb/ft³.

These examples demonstrate why density values can look dramatically different depending on the selected unit.

Density, Mass and Volume

Density is directly connected to mass and volume.

The three important formulas are:

ρ = m/V

m = ρV

V = m/ρ

If you know any two of these quantities, you can calculate the third.

Example: Find Mass From Density

Suppose a material has:

Density = 2700 kg/m³

and:

Volume = 0.5 m³

Then:

m = ρV

m = 2700 × 0.5

m = 1350 kg

So the material has a mass of 1350 kg.

Example: Find Volume From Density

Suppose a liquid has:

Mass = 850 kg

and:

Density = 850 kg/m³

Then:

V = m/ρ

V = 850/850

V = 1 m³

This relationship is fundamental to material calculations, fluid calculations, manufacturing, and engineering.

Density and Specific Volume

Density and specific volume are closely related but represent opposite relationships.

Density is:

mass ÷ volume

Specific volume is:

volume ÷ mass

Therefore:

specific volume = 1/density

and:

density = 1/specific volume

For example, if density is:

1000 kg/m³

then specific volume is:

1/1000 = 0.001 m³/kg

This relationship is particularly important in thermodynamics and fluid engineering.

If you regularly work with both quantities, the Specific Volume Converter can be useful alongside the Density Converter.

Density vs Weight

Density describes mass per unit volume.

Weight is a force caused by gravity.

These are not the same quantity.

For example:

kg/m³ is a density unit.

N is a force unit.

A common source of confusion is the use of pounds in US customary units. A pound can refer to pound mass or pound force depending on the context.

When converting density, make sure the mass unit is being used consistently.

This distinction becomes particularly important in engineering calculations involving gravity, force, and material properties.

Density and Buoyancy

Density also helps explain why objects float or sink.

When an object is placed in a fluid, its behavior depends partly on its average density compared with the density of the surrounding fluid.

If an object’s average density is lower than the fluid’s density, it can float.

If its average density is greater, it tends to sink.

This principle is important in ship design, fluid mechanics, hydrometers, material testing, and many everyday applications.

Density in Engineering and Construction

Density values are used throughout engineering and construction.

Concrete

Engineers use density when estimating the mass of concrete structures and calculating loads.

Asphalt

Density is important when determining material quantities and compaction quality in road construction.

Metals

Material density helps engineers estimate the mass of components before manufacturing.

Fluids

Fluid density is required in calculations involving pressure, flow, pumping, storage, and buoyancy.

Soil and Aggregates

Construction and geotechnical engineering use density measurements to assess materials and compaction.

Petroleum

Oil and fuel specifications frequently use density or closely related measures to characterize fluids.

Because different industries use different unit systems, a density converter can simplify the conversion stage before performing the main engineering calculation.

Common Mistakes When Converting Density

1. Forgetting that volume is cubed

Length conversions cannot be applied directly to volume.

For example:

1 m = 100 cm

but:

1 m³ = 1,000,000 cm³

The conversion factor is cubed because volume has three dimensions.

This is one of the main reasons density conversions can be more complicated than ordinary mass conversions.

2. Confusing density with mass

A value such as:

1000 kg/m³

does not mean the object has a mass of 1000 kg.

It means that each cubic metre of the material has a mass of 1000 kg.

The actual mass depends on the volume.

3. Confusing density with weight

Density is mass per volume.

Weight is force.

They are related through gravity but are not interchangeable.

4. Mixing US and Imperial gallons

US gallons and Imperial gallons have different volumes.

Always check which gallon is being used when working with lb/gal.

5. Reversing the conversion

For example:

1 g/cm³ = 1000 kg/m³

not:

1 g/cm³ = 0.001 kg/m³

The reverse relationship is:

1 kg/m³ = 0.001 g/cm³

6. Rounding too early

Keep enough precision during intermediate calculations and round the final result rather than repeatedly rounding conversion factors.

Why Use the CalculatorKits Density Converter?

The CalculatorKits Density Converter is designed for quick density conversions across metric, scientific, and imperial units.

The current tool provides:

1. 25 density units in one converter.
2. kg/m³ as the base unit for its conversion system.
3. Instant conversion results as values and units are selected.
4. Common scientific units such as kg/m³ and g/cm³.
5. Liquid related units such as g/L and kg/L.
6. Imperial and US engineering units including lb/ft³, lb/in³, lb/gal, and slug/ft³.
7. Common conversion presets for frequently used density conversions.
8. Browser based calculations.
9. No registration required.
10. Local processing, with the tool stating that calculations are performed in the browser and data is not uploaded or stored.

The tool states that it uses official SI constants, avoids rounding until final display, and is intended for informational and calculation support. For legal, certified, or safety critical measurements, the result should be verified against the applicable official measurement source.

Density Converter FAQs

What is the SI unit of density?

The SI unit of density is kilogram per cubic metre (kg/m³). BIPM lists density or mass density as kg m⁻³ among SI derived quantities.

What is the formula for density?

The basic density formula is:

ρ = m/V

where ρ is density, m is mass, and V is volume.

How do I convert kg/m³ to g/cm³?

Divide the value in kg/m³ by 1000.

g/cm³ = kg/m³ ÷ 1000

For example:

1000 kg/m³ = 1 g/cm³

How do I convert g/cm³ to kg/m³?

Multiply the value in g/cm³ by 1000.

kg/m³ = g/cm³ × 1000

Therefore:

2 g/cm³ = 2000 kg/m³

How do I convert kg/m³ to g/L?

The numerical value is the same:

1 kg/m³ = 1 g/L

Therefore:

850 kg/m³ = 850 g/L

How do I convert kg/m³ to lb/ft³?

Multiply by approximately 0.062428.

For example:

1000 kg/m³ ≈ 62.428 lb/ft³

NIST gives the corresponding conversion factor for lb/ft³.

What is the density of water?

A commonly used reference value is approximately:

1000 kg/m³ = 1 g/cm³

The actual density of water varies with temperature and pressure, so this value should be treated as a common reference rather than a universal value for every condition.

What is the difference between density and specific volume?

Density is mass divided by volume:

ρ = m/V

Specific volume is volume divided by mass:

v = V/m

For a consistent unit system, they are reciprocals:

v = 1/ρ

What is the difference between density and weight?

Density measures mass per unit volume.

Weight is a force caused by gravity.

Therefore, density is commonly expressed in kg/m³, while weight is expressed in newtons in SI.

Can density be converted between metric and imperial units?

Yes. The CalculatorKits Density Converter supports both metric and imperial density units, including kg/m³, g/cm³, lb/ft³, lb/in³, lb/gal, and slug/ft³.

What is 1 g/cm³ in kg/m³?

1 g/cm³ = 1000 kg/m³

This is one of the most commonly used density conversions. NIST confirms the relationship.

What is 1 kg/m³ in g/cm³?

1 kg/m³ = 0.001 g/cm³

Is 1 kg/m³ equal to 1 g/L?

Yes.

1 kg/m³ = 1 g/L

This is a particularly convenient relationship for liquid density calculations.

How many density units does the CalculatorKits converter support?

The current CalculatorKits Density Converter supports 25 density units. The tool includes common units such as kg/m³, g/cm³, g/L, lb/ft³, lb/in³, lb/gal, and slug/ft³, along with additional units.

Is the CalculatorKits Density Converter free?

Yes. The current tool is presented as free to use and does not require registration.

Does the Density Converter store my calculations?

CalculatorKits states that calculations are performed locally in the browser and that data is not uploaded or stored.

Related CalculatorKits Tools

If you are working with density, materials, fluids, and engineering calculations, these four CalculatorKits tools are useful companions:

1. Specific Volume Converter
   Convert specific volume units and work with the reciprocal relationship between density and specific volume.
2. Weight and Mass Converter
   Convert mass and weight related units used when working with material quantities and density calculations.
3. Pressure Converter
   Convert pressure units used in fluid mechanics, engineering, and material calculations.
4. Acceleration Converter
   Convert acceleration units for physics and engineering calculations involving mass, force, and motion.

Conclusion

Density describes how much mass is contained within a given volume. It is a fundamental property used in science, engineering, construction, manufacturing, chemistry, fluid mechanics, and material analysis.

The SI unit is kg/m³, but you may encounter many other forms, including:

g/cm³

g/L

kg/L

lb/ft³

lb/in³

lb/gal

slug/ft³

The most useful relationships include:

1 g/cm³ = 1000 kg/m³

1 kg/m³ = 1 g/L

1 kg/L = 1000 kg/m³

1 kg/m³ ≈ 0.062428 lb/ft³

1 lb/ft³ ≈ 16.0185 kg/m³

1 lb/in³ ≈ 27,679.9 kg/m³

1 slug/ft³ ≈ 515.379 kg/m³

When you need to switch between these units, the CalculatorKits Density Converter provides a quick way to perform the conversion without manually calculating mass and volume conversion factors.

The tool currently supports 25 density units, uses kg/m³ as its base unit, and provides common conversion presets for frequently used density measurements.

For normal educational, scientific, and engineering calculations, an online converter can save time and reduce repetitive arithmetic. For certified measurements, regulated applications, or safety critical engineering work, always verify the final value against the appropriate standard, material specification, or measurement procedure.

References

1. BIPM, The International System of Units
2. BIPM, SI Base Units
3. BIPM, SI Brochure
4. NIST, Guide to the SI, Appendix B Conversion Factors
5. NIST, Factors for Units Listed by Kind of Quantity

• Written and reviewed by the CalculatorKits Editorial Team
• Last Updated: September 10, 2026