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Density Calculator

Find density from mass and volume, or find mass or volume from density, in g/cm³, kg/m³ and lb/ft³.

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StepWorking
Density changes with temperature and, for gases, with pressure. Values in the table are typical figures near room temperature unless stated.

Quick Answer

Density is mass divided by volume: ρ = m ÷ V. A block of aluminum with a mass of 540 g and a volume of 200 cm³ has a density of 2.7 g/cm³, which is 2,700 kg/m³. Rearrange to find mass (m = ρ × V) or volume (V = m ÷ ρ).

Last updated: 2 November 2026 ·How we calculate this: density formula ρ = m ÷ V

Table of Contents

How This Density Calculator Works

Choose what you want to find: density, mass or volume. Enter the other two values with their units. The calculator converts everything to grams and cubic centimeters, applies the formula, and shows the answer in several units.

Quick explanation: density = mass ÷ volume.

  • g/cm³: common in science. Water is about 1 g/cm³.
  • kg/m³: the SI unit. Multiply g/cm³ by 1,000.
  • lb/ft³: common in US engineering. Multiply g/cm³ by about 62.43.

How to Use the Density Calculator

  1. Choose whether to find density, mass or volume.
  2. Enter the two values you know.
  3. Pick the units for mass and volume.
  4. Press Calculate.
  5. Read the answer in several units, with the steps.

Core Formulas

  • Density: ρ = m ÷ V
  • Mass: m = ρ × V
  • Volume: V = m ÷ ρ
  • Unit change: 1 g/cm³ = 1,000 kg/m³ ≈ 62.43 lb/ft³

Key Terms

  • Density (ρ): the mass of a substance per unit of volume.
  • Mass: the amount of matter in an object, measured in grams or kilograms.
  • Volume: the space an object takes up.
  • Specific gravity: density compared with water, with no units.
  • Buoyancy: the upward push of a fluid, which lets less dense objects float.

Worked Example

A gold ring has a mass of 7.72 g. What is its volume, if gold is 19.32 g/cm³?

  • V = m ÷ ρ
  • V = 7.72 ÷ 19.32 = 0.3996 cm³
  • That is about 0.4 mL

Real-Life Examples

  • Will it float? an object floats in water if its density is below about 1 g/cm³. Oak at around 0.75 g/cm³ floats, while steel at about 7.85 sinks.
  • Checking metal: a coin of 31.1 g that displaces 2.96 mL of water has a density of about 10.5 g/cm³, close to silver.
  • Shipping weight: 2 m³ of water weighs about 2,000 kg, because water is about 1,000 kg/m³.
  • Cooking oil: 1 L of olive oil at about 0.91 g/cm³ weighs about 910 g.
  • A school lab: a rock of 150 g raises the water in a cylinder from 50 mL to 105 mL. Its volume is 55 cm³, so its density is about 2.73 g/cm³, close to common rock such as granite.

Density vs Specific Gravity

  • Density: mass per volume, with units such as g/cm³.
  • Specific gravity: density compared with water. It has no units.
  • The link: because water is about 1 g/cm³, specific gravity has nearly the same number as density in g/cm³.
  • Example: aluminum at 2.7 g/cm³ has a specific gravity of about 2.7.

Densities of Common Materials

Materialg/cm³kg/m³
Air (sea level, 15°C)0.0012251.225
Ethanol0.789789
Ice0.917917
Water (4°C)1.0001,000
Aluminum2.702,700
Iron7.877,870
Copper8.968,960
Gold19.3219,320

What Affects Density

  • Temperature: most materials expand when warm, lowering density.
  • Pressure: gases become much denser when compressed.
  • Purity: mixtures and alloys differ from pure materials.
  • Air gaps: wood, foam and powders contain air, which lowers their bulk density.

Common Mistakes to Avoid

  • Mixing units. Convert mass and volume to matching units before dividing.
  • Confusing mass and weight. Use mass in grams or kilograms.
  • Using total volume for hollow objects. Hollow items have a lower average density.
  • Forgetting temperature. Liquid densities change as they warm up.
  • Reading mL as L. 1 mL is 1 cm³, and 1 L is 1,000 cm³.

Frequently Asked Questions

Divide mass by volume. 540 g ÷ 200 cm³ = 2.7 g/cm³.

About 1 g/cm³, or 1,000 kg/m³, at 4°C. It is slightly lower at room temperature.

Put it in water and measure how much the water level rises. That rise is its volume.

Kilograms per cubic meter (kg/m³).

Ice is less dense than liquid water, about 0.917 g/cm³, so it floats.

Multiply by 1,000. 2.7 g/cm³ = 2,700 kg/m³.

Multiply by about 62.43. Water is about 62.4 lb/ft³.

Yes. One milliliter is exactly one cubic centimeter, so the two numbers are always the same.

Osmium, at about 22.6 g/cm³, is usually listed as the densest, with iridium very close behind.

Weigh an empty measuring cylinder, add a known volume of liquid, weigh it again, and divide the mass of the liquid by its volume.

Yes. Seawater is about 1.02 to 1.03 g/cm³, which is why it is easier to float in the sea than in a pool.

The density of a loose material such as soil or gravel, including the air between the pieces. It is lower than the density of the solid material.

References & Sources

SourceUsed ForLink
NIST, Unit conversion Metric and US customary units. https://www.nist.gov/pml/owm/metric-si/unit-conversion
Wikipedia, Density Density definition and common values. https://en.wikipedia.org/wiki/Density