Density calculator
Density, mass or volume of a substance from ρ = m ÷ V.
Fill in the fields and the result will appear here automatically.
Relates mass, occupied volume and average mass density. Inputs always use kg, m³ and kg/m³: entering grams does not switch the units. Density is additionally converted to g/cm³. Average density depends on the volume measured: a porous body’s external volume includes voids, while the material volume excludes them. Temperature, pressure, composition and porosity are not assigned automatically.
How it works
Formula and logic
ρ = m/V, m = ρV and V = m/ρ. Since 1 g/cm³ = 1000 kg/m³, the g/cm³ row is ρ/1000. Using external volume includes pores in the denominator; the tool does not subtract them automatically. Zero mass in a specified positive volume gives zero average density.
Example
1000 kg in 1 m³ gives 1000 kg/m³ = 1 g/cm³. This is a convenient rounded example, not water’s exact density under every condition. A 5.4 kg part occupying 0.002 m³ gives 2700 kg/m³ = 2.7 g/cm³; at density 2700 and volume 0.5 m³, mass is 1350 kg.
Fields and units
- What to find — list option
- Mass — kg
- Volume — m³
- Density — kg/m³
- Volume — m³
- Mass — kg
- Density — kg/m³
How to use
- — Choose density, mass or volume.
- — Use mass in kg, volume in m³ and density in kg/m³; for example, 2 litres = 0.002 m³.
- — For density or mass, volume must be positive; mass or density may be zero.
- — Finding a positive volume requires positive mass and density; use a reference density for the relevant conditions.
Method and limitations
- Calculation method
- Formula and logic
- Data or methodology source
- OpenStax: average mass density and kg/m³ ↔ g/cm³
- Limitation
- Average mass density at specified conditions and volume definition; temperature, pressure, porosity and composition are not modelled separately.
FAQ
How is this different from the density converter?
The converter changes units for a known density. Here two related quantities determine the third, with fixed SI input fields.
Why show g/cm³, and is water exactly 1 g/cm³?
The unit is convenient for materials: 1000 kg/m³ equals exactly 1 g/cm³. Real water density varies with temperature, pressure and composition; 1000 is a rounded example.
Can I get the mass of a part from its volume?
Yes, m = ρV. Density and volume must describe the same part: material density cannot be combined with the outer volume of a hollow part without accounting for voids.
How are voids and porosity included?
Through the volume you choose. Mass divided by external volume including pores gives average or bulk density; pore-free material density is different.
How does density differ from specific weight?
Density is mass per volume in kg/m³. Specific weight is gravitational force per volume in N/m³, equal to ρg for the chosen gravity.
How can I measure an irregular body’s volume?
For an impermeable object, liquid displacement can measure volume. Dissolving, absorption, open pores and trapped bubbles can alter the measurement; choose a method matching the intended volume.