Density Converter

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g/cm³ • kg/m³ • lb/ft³ • lb/in³

Density Value ⓘ

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Enter a density value to convert

How to Use the Density Converter

Enter a density value — e.g. 1 for water, or 7.87 for the density of iron in g/cm³.
Select From unit — g/cm³ (chemistry), kg/m³ (SI/engineering), lb/ft³ (US construction), lb/in³ (machining).
Read the result — including specific gravity (density relative to water).
Reference point — water is exactly 1 g/cm³ = 1,000 kg/m³ at 4°C, the basis for specific gravity.

Benefits

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Chemistry & Lab

Convert solution and reagent densities between g/mL and kg/m³. Specific gravity tells you if a substance floats or sinks in water.

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Engineering & Materials

Material densities in lb/ft³ (US) vs kg/m³ (SI) for structural load, buoyancy, and weight estimates.

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Cooking & Baking

Convert ingredient densities to translate between weight and volume measurements in recipes.

Density Conversion Guide — g/cm³, kg/m³, lb/ft³

Density is mass per unit volume, and the reference substance is water: exactly 1 gram per cubic centimeter (g/cm³), which equals 1,000 kilograms per cubic meter (kg/m³) or 62.43 pounds per cubic foot (lb/ft³) at 4°C. The g/cm³ unit is most common in chemistry (and equals g/mL, since 1 cm³ = 1 mL), while kg/m³ is the SI standard used in physics and engineering. In the US construction and materials industries, lb/ft³ dominates, and precision machining uses lb/in³.

Specific gravity is density relative to water (dimensionless): a substance with specific gravity below 1 floats, above 1 sinks. Numerically, specific gravity equals the density in g/cm³. For example, gold has a density of 19.3 g/cm³ (specific gravity 19.3), aluminum is 2.7 g/cm³, and gasoline is about 0.74 g/cm³ (which is why it floats on water). Converting density correctly is essential for buoyancy calculations, material selection, shipping weight estimates, and verifying the purity of metals and liquids.

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Common Liquid Densities

Water: 1.0 g/cm³. Gasoline: 0.74. Milk: 1.03. Honey: 1.42. Mercury: 13.6. Seawater: 1.025. Olive oil: 0.92 (floats on water).

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Common Metal Densities

Aluminum: 2.7 g/cm³. Iron: 7.87. Steel: 7.85. Copper: 8.96. Lead: 11.34. Gold: 19.3. Titanium: 4.51 (strong & light).

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Construction Materials

Concrete: 2,400 kg/m³ (150 lb/ft³). Wood (pine): 500 kg/m³. Brick: 1,920 kg/m³. Glass: 2,500 kg/m³.

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Specific Gravity

Density relative to water. SG < 1 floats, SG > 1 sinks. Equals density in g/cm³. Used to test battery acid, fuel, and precious metals.

Density Conversion FAQ

How do you convert g/cm³ to kg/m³? ▾

Multiply by 1,000. So 1 g/cm³ = 1,000 kg/m³, and 7.87 g/cm³ (iron) = 7,870 kg/m³. This is because there are 1,000 grams in a kilogram and 1,000,000 cubic centimeters in a cubic meter, giving a net factor of 1,000. Note that g/cm³ and g/mL are identical units.

Is g/mL the same as g/cm³? ▾

Yes, exactly. One milliliter (mL) is defined as one cubic centimeter (cm³), so g/mL and g/cm³ are identical units — both equal 1,000 kg/m³ for water. Chemists often write g/mL for liquids and g/cm³ for solids, but the numbers are interchangeable.

What is specific gravity? ▾

Specific gravity (SG) is the ratio of a substance's density to the density of water, making it a dimensionless number. Since water is 1 g/cm³, the specific gravity of any substance equals its density in g/cm³. Gold's SG is 19.3, meaning it's 19.3 times denser than water. SG below 1 means a substance floats; above 1 means it sinks.

How do you convert density to lb/ft³? ▾

To convert kg/m³ to lb/ft³, divide by 16.0185. So water at 1,000 kg/m³ = 62.43 lb/ft³. To convert from g/cm³ to lb/ft³, multiply by 62.428. This is widely used in US construction for estimating the weight of concrete, soil, gravel, and structural materials by volume.