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Density Calculator

Calculate density, mass, or volume instantly with full unit conversion and material comparison

Updated

What is the Density Calculator?

The Density Calculator finds density, mass, or volume from any two known values using the standard physics formula ρ = m / V. Enter values in whatever units you have on hand — grams, pounds, litres, cubic inches, and more — and get an instant, unit-accurate result.

Density tells you how tightly matter is packed into a given space. It's the property that determines whether an object floats or sinks, how materials are identified in labs and workshops, and how engineers select the right material for a job. This tool is built for students checking homework, hobbyists identifying metals or gemstones, and professionals in engineering, manufacturing, shipping, and construction who need quick, reliable density conversions.

Unlike most online density calculators that lock you into a single unit system, this tool converts freely between metric and imperial mass and volume units, shows your result across several density units at once, and compares it against a reference table of common materials so you instantly know what you're likely looking at.

How it works

  1. Choose what you want to solve for. Pick Density, Mass, or Volume depending on which value is unknown. The calculator automatically shows the two input fields needed for that calculation.

  2. Enter your known values. Type in the numbers and select the matching units from the dropdowns. Mass supports units from milligrams to tonnes; volume supports everything from cubic millimetres to gallons.

  3. Read the result instantly. The calculator applies the density formula:

ρ=mV\rho = \frac{m}{V}

where ρ is density, m is mass, and V is volume. Rearranged forms are used automatically when solving for mass (m = ρV) or volume (V = m / ρ).

  1. Compare across units. Your result is shown simultaneously in kg/m³, g/cm³, kg/L, and lb/ft³, so you don't need to run a separate conversion.

  2. Identify the material. The calculator matches your computed density against a built-in reference table of common metals, liquids, woods, and gases, showing the closest matches and how far off each one is — a fast way to sanity-check lab results or guess an unknown material.

  3. Check buoyancy. A built-in indicator tells you whether an object of that density would float or sink in fresh water, based on water's reference density of 1000 kg/m³.

All calculations run locally in your browser — no data is uploaded or stored.

Examples

Find the density of a gold sample

Solve for density when mass and volume are known

Mass: 500 g, Volume: 25.9 cm³
Density: 19.31 g/cm³ (matches pure gold)

Find the mass of a known volume of water

Solve for mass when density and volume are known

Density: 1000 kg/m³, Volume: 2 L
Mass: 2 kg

Find the volume of a steel block

Solve for volume when density and mass are known

Density: 7850 kg/m³, Mass: 15.7 kg
Volume: 2 L (2000 cm³)

Frequently asked questions

What is the formula for density?

Density is calculated as ρ = m / V, where mass (m) is divided by volume (V). The result is typically expressed in kilograms per cubic metre (kg/m³) or grams per cubic centimetre (g/cm³).

How do I find mass or volume instead of density?

Switch the calculator's mode to "Solve for Mass" or "Solve for Volume." The formula is rearranged automatically: mass is found with m = ρV, and volume is found with V = m / ρ.

What units does this density calculator support?

Mass units include milligrams, grams, kilograms, tonnes, ounces, pounds, stone, and both US and UK tons. Volume units include millilitres, litres, cubic metres, cubic inches, cubic feet, and US/UK gallons, quarts, pints, and cups. Density results are shown in kg/m³, g/cm³, kg/L, and lb/ft³.

How do I know if an object will float or sink?

Compare its density to water, which is about 1000 kg/m³ (1 g/cm³) at 4°C. Objects with a lower density than water float, and objects with a higher density sink. This calculator shows that comparison automatically with every result.

Why is my calculated density slightly different from a textbook value?

Small differences usually come from measurement precision, temperature, or air pockets and impurities in the sample. Reference densities (like 19.3 g/cm³ for gold) assume pure, solid material at standard temperature and pressure.

What's the difference between density and specific gravity?

Specific gravity is the ratio of a substance's density to the density of water (or air, for gases), so it has no units. Density itself is always expressed in mass-per-volume units like kg/m³ or g/cm³.

Can I use this calculator for gases and liquids, not just solids?

Yes. The density formula applies to any state of matter. Just make sure your volume measurement accounts for the full space the substance occupies, since gases and liquids take the shape of their container.

Is my data stored when I use this calculator?

No. All calculations happen directly in your browser. Nothing you enter is sent to a server or saved anywhere.

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