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Density Converter

Convert between kg/m³, g/cm³, lb/ft³, lb/gal, and g/mL — for materials, fluids, chemistry, and engineering.

Density

kg/m³, g/cm³, lb/ft³

From
Result
0.001

1 kg/m³ = 0.001 g/cm³

Popular conversions

What Is a Density Converter?

A density converter translates mass-per-volume between units — kilograms per cubic metre to grams per cubic centimetre, pounds per cubic foot to kilograms per cubic metre. Density is how much mass is packed into a given volume, the property that decides whether something floats, how heavy a tank of fluid is, and what material you're holding. The SI unit is kg/m³.

This converter routes through kg/m³. A handy anchor runs through it: water is almost exactly 1,000 kg/m³ = 1 g/cm³ = 1 g/mL, so many densities are quoted relative to water (specific gravity). The tool bridges the metric (kg/m³, g/cm³) and imperial (lb/ft³, lb/gal) systems used across materials science, fluids, and shipping.

This is one category of the full Unit Converter — pair it with our percentage calculator or scientific calculator for related everyday maths.

How Density Conversion Works

Everything routes through kg/m³

Each unit has a fixed kg/m³ factor. The converter normalises your input to kg/m³, then projects it into every other density unit.

Density = mass ÷ volume

ρ = m/V. The same material always has the same density regardless of how much you have — it's an intrinsic property, not a total.

Water is the reference

Water is ~1,000 kg/m³ = 1 g/cm³. Specific gravity expresses a density relative to water, so SG 0.8 means 800 kg/m³.

Both mass and volume units convert

Because density combines mass and volume, its conversion factors combine a mass ratio and a volume ratio — which is why g/cm³ to kg/m³ is a clean ×1,000.

Core Density Conversion Factors

Multiply to reach kg/m³; divide to come back.

g/cm³ → kg/m³

× 1000

One gram per cubic centimetre is 1,000 kg/m³. Water is 1 g/cm³ = 1,000 kg/m³.

lb/ft³ → kg/m³

× 16.0185

One pound per cubic foot is 16.0185 kg/m³, the US-to-SI density bridge.

Specific gravity

SG = ρ / ρ_water

Density relative to water (1,000 kg/m³). SG 13.6 (mercury) means 13,600 kg/m³.

How to Use the Density Converter

  1. 1

    Enter the density value

    Type the density you want to convert — a material property, a fluid density, a concentration.

  2. 2

    Choose the 'from' unit

    Pick kg/m³, g/cm³, lb/ft³, lb/gal, or g/mL as your starting unit.

  3. 3

    Choose the 'to' unit

    Select the target unit, or swap the two to reverse direction.

  4. 4

    Read every unit at once

    The all-units table shows the density across metric and imperial units together for a quick check.

Key Density Concepts

Density (ρ)

Mass per unit volume, kg/m³ in SI. An intrinsic material property: a small and a large block of the same steel have identical density.

Specific gravity

The ratio of a substance's density to water's. Dimensionless and unit-free, so SG 2.7 (aluminium) means 2,700 kg/m³ anywhere.

g/cm³ ≈ relative to water

Because water is 1 g/cm³, a density in g/cm³ reads almost directly as specific gravity — gold's 19.3 g/cm³ is SG 19.3.

Temperature dependence

Density changes with temperature (and pressure for gases). Liquid densities are usually quoted at a stated temperature like 20 °C.

Real-World Density Conversions

💧

Water reference

Water is 1,000 kg/m³ = 1 g/cm³ = 62.4 lb/ft³. The benchmark every other density is compared against.

🛢️

Fuel and oil

Petrol is about 740 kg/m³ (0.74 g/cm³); crude oil ~870 kg/m³. Fuel density sets the mass of a tank's contents.

🪙

Metals

Aluminium is 2,700 kg/m³, steel ~7,850, gold 19,300. Density distinguishes metals and detects counterfeits.

🌳

Wood and materials

Oak is about 750 kg/m³, balsa just 160. Material density drives structural weight and buoyancy.

🧪

Chemistry

Mercury is 13,600 kg/m³ (SG 13.6); ethanol 789. Lab work converts between g/mL and kg/m³ constantly.

🚢

Shipping and buoyancy

Seawater is ~1,025 kg/m³, denser than fresh water — which is why ships float slightly higher at sea than in a river.

Best Practices for Density Conversion

  • ✓Remember water = 1,000 kg/m³. Water at 1 g/cm³ = 1,000 kg/m³ is the universal anchor. If a converted density is near it, your fluid is roughly water-like.
  • ✓State the temperature. Liquid and gas densities depend on temperature. Quote densities at a reference temperature (often 20 °C) for them to be meaningful.
  • ✓Use specific gravity for unit-free comparison. Specific gravity (density ÷ water) is dimensionless, so it compares materials without worrying about units at all.
  • ✓Don't equate mass and volume. Density is the bridge between them. A litre of oil isn't a kilogram — multiply volume by density to get mass.
  • ✓Mind gas vs liquid scales. Gas densities (air ~1.2 kg/m³) are far smaller than liquids. Check the magnitude so you don't confuse a gas figure with a liquid one.

Common Density Conversion Mistakes

Assuming 1 L = 1 kg for everything

That holds only for water. A litre of petrol is 0.74 kg, of mercury 13.6 kg — use density, not a blanket equivalence.

Ignoring temperature

Quoting a liquid density without its temperature makes it ambiguous, since density drifts as materials expand or contract with heat.

Mishandling the g/cm³ ↔ kg/m³ factor

The factor is exactly 1,000. Forgetting it puts a metal's density off by three orders of magnitude.

Confusing density with specific gravity

Specific gravity is unit-free (density ÷ water). Treating an SG value as kg/m³ understates the real density 1,000-fold.

Why Density Conversion Matters

Density decides flotation, structural weight, fuel mass, material identification, and chemical proportions — and it's quoted in kg/m³, g/cm³, lb/ft³, or as specific gravity depending on the discipline. Because it links mass and volume, a wrong density conversion misjudges how heavy a tank of fluid is or whether a load will float, with real engineering and safety stakes.

The water anchor (1,000 kg/m³ = 1 g/cm³) makes density intuitive once the units line up, but mixing systems or ignoring temperature undermines it. A converter that routes through kg/m³ and exposes g/cm³, lb/ft³, and specific gravity together keeps materials, fluids, and chemistry calculations consistent.

Built for materials engineers, chemists, fuel and fluid specialists, and students converting between kg/m³, g/cm³, and lb/ft³.

Linear unit factors follow the BIPM SI brochure, the NIST Guide to the SI, and ISO 80000. Currency rates load live from open.er-api.com; crypto prices from CoinGecko. See our methodology and editorial policy. Educational only — not certified for regulated trading, settlement, medical, or aerospace use.

Density Converter FAQs

Multiply grams per cubic centimetre by 1,000 to get kilograms per cubic metre. So water at 1 g/cm³ is 1,000 kg/m³, and aluminium at 2.7 g/cm³ is 2,700 kg/m³. The factor is exactly 1,000 because a gram is 1/1,000 kg and a cm³ is 1/1,000,000 m³.

Water has a density of about 1,000 kg/m³, equal to 1 g/cm³, 1 g/mL, or 62.4 lb/ft³ at 4 °C (its densest point). It's the universal reference for density, which is why specific gravity is defined relative to water.

Specific gravity is the ratio of a substance's density to the density of water (1,000 kg/m³). It's dimensionless, so a specific gravity of 13.6 (mercury) means a density of 13,600 kg/m³. Because water is 1 g/cm³, a density in g/cm³ is numerically equal to its specific gravity.

Multiply pounds per cubic foot by 16.0185 to get kilograms per cubic metre. So a material at 50 lb/ft³ is about 801 kg/m³. The factor combines the pound-to-kilogram and cubic-foot-to-cubic-metre conversions.

Yes. Most substances expand when heated, lowering their density, so liquid and gas densities are quoted at a reference temperature (commonly 20 °C or 4 °C for water). Solids change least; gases change most, since they also depend strongly on pressure.

It uses exact derived factors (1 g/cm³ = 1,000 kg/m³, 1 lb/ft³ = 16.018463 kg/m³) and routes every conversion through kg/m³ at full precision, so the result is exact to your input precision at the implied temperature.

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