Density Calculator
Solve for density, mass, or volume — ρ = m/V — across SI and imperial units.
Written by Golam Rabbani, Founder & Lead Engineer
How to use this density calculator
- Pick which value to solve for: density, mass, or volume.
- Enter the other two values and pick their units (g/kg/mg/lb/oz for mass; cm³/mL/L/m³/in³/ft³ for volume).
- Press Calculate to see density in g/cm³ and the equivalent in kg/m³.
- Use Copy to grab the result or Reset to clear inputs.
About this density calculator
Density (ρ) is the mass of a substance per unit volume: ρ = m ⁄ V. Density distinguishes lead from aluminium, freshwater from salt water, and answers floatation problems via Archimedes' principle (anything denser than water sinks; anything less dense floats). The density calculator solves the relation in any direction — give it mass and volume and it returns ρ; give it density and one of the other two and it returns the third.
Worked example: a 100 g chunk of aluminium displaces 37.04 cm³ of water in a graduated cylinder. Density = 100 ⁄ 37.04 = 2.70 g/cm³ — exactly the textbook value for aluminium (2,700 kg/m³). Going the other way: how much would a 0.5 L bottle of olive oil weigh, given olive oil's density of 0.92 g/cm³? Volume in cm³ is 500. Mass = 0.92 × 500 = 460 g. Compare to a 0.5 L bottle of water (density 1.00 g/cm³), which weighs 500 g — that 40 g difference is why oil floats on water.
FAQ
- What units does the calculator output?
- Density is reported in g/cm³ (also known as g/mL) with an automatic kg/m³ conversion (1 g/cm³ = 1000 kg/m³). Mass is in grams and volume in cubic centimetres.
- Is g/cm³ the same as g/mL?
- Yes. By definition 1 mL = 1 cm³ exactly. The two units are interchangeable.
- What is the density of water?
- Exactly 1.000 g/cm³ at 4 °C, dropping slightly to 0.997 g/cm³ at 25 °C. The classic SI definition of density was originally tied to water for that reason.
- Why does the calculator support imperial units?
- Engineering and trade documents in the US still quote weights in pounds and volumes in cubic feet. The tool converts those to grams and cubic centimetres internally using exact factors (1 lb = 453.59237 g, 1 ft³ = 28316.846592 cm³).
- Can I get specific gravity?
- Specific gravity is density relative to water (≈ 1 g/cm³). Just read the g/cm³ result and treat it as specific gravity to two decimals — they match closely at typical conditions.
- Is the density calculator free?
- Yes — free, no signup, runs in your browser.