Density Calculator
Find density, mass or volume — know any two, get the third
Density = Mass ÷ Volume. Enter any two values and get the third in g/cm³, kg/m³, lb/ft³ and every common unit at once — plus a quick check whether the object floats or sinks in water.
Calculate now — free
Worked Examples
See exactly how the density formula is applied, step by step, for each type of problem.
A metal block has a mass of 500 g and a volume of 200 cm³. Find its density.
- Apply the formula: Density = Mass ÷ Volume
- Density = 500 g ÷ 200 cm³
- To get kg/m³, multiply g/cm³ by 1,000
Aluminium has a density of 2.7 g/cm³. What is the mass of a 50 cm³ piece?
- Apply the formula: Mass = Density × Volume
- Mass = 2.7 g/cm³ × 50 cm³
- The cm³ units cancel, leaving grams
Ethanol has a density of 0.79 g/mL. What volume does 790 g of ethanol occupy?
- Apply the formula: Volume = Mass ÷ Density
- Volume = 790 g ÷ 0.79 g/mL
- 1,000 mL = 1 litre
An object has a mass of 300 g and a volume of 400 cm³. Will it float in water?
- Density = 300 g ÷ 400 cm³ = 0.75 g/cm³
- Water's density is 1 g/cm³ (1,000 kg/m³)
- 0.75 is less than 1, so the object is less dense than water
Try any of these with the shortcut chips in the calculator above, or swap in your own numbers.
Density of Common Materials
Handy reference values for checking your answer or solving problems that don't give the density.
| Material | kg/m³ | g/cm³ |
|---|---|---|
| Air (at 20°C) | 1.2 kg/m³ | 0.0012 |
| Ethanol | 789 kg/m³ | 0.789 |
| Ice | 917 kg/m³ | 0.917 |
| Water (at 4°C) | 1,000 kg/m³ | 1.00 |
| Aluminium | 2,700 kg/m³ | 2.70 |
| Iron | 7,874 kg/m³ | 7.87 |
| Copper | 8,960 kg/m³ | 8.96 |
| Silver | 10,490 kg/m³ | 10.49 |
| Lead | 11,340 kg/m³ | 11.34 |
| Mercury | 13,534 kg/m³ | 13.53 |
| Gold | 19,320 kg/m³ | 19.32 |
Values are approximate and change slightly with temperature and purity. Use the figure given in your question or textbook if it differs.
Free Density Calculator — For Physics & Chemistry Numericals
Density tells you how much mass is packed into a given volume, and it's one of the most frequently tested ideas in school physics and chemistry. The formula is Density = Mass ÷ Volume (written ρ = m / V). Rearranged, that gives Mass = Density × Volume and Volume = Mass ÷ Density, so if you know any two values, you can always find the third.
Where students lose marks is usually the units. A question might give mass in grams and volume in litres, or ask for the answer in kg/m³ when your working is in g/cm³. This calculator lets you pick the unit for each value separately and returns the answer in several common units at once, so you don't need a separate conversion step. A quick rule to remember: 1 g/cm³ = 1,000 kg/m³, and since 1 mL is the same as 1 cm³, g/mL and g/cm³ are identical.
Use the Find Density tab when you know mass and volume (it also tells you whether the object floats or sinks in water), Find Mass when you know density and volume, and Find Volume when you know mass and density. These are the standard SI-based formulas used in CBSE, TN Board, NEET and JEE.
Related tools: the volume converter and mass converter handle standalone unit conversions, and the speed, distance and time calculator covers the other classic physics formula. For a full word problem, StudyHelpAI's Physics and Chemistry solvers can walk you through it step by step.
← Back to all unit convertersDensity — common questions
Density = Mass ÷ Volume, written as ρ = m / V. Rearranged, Mass = Density × Volume and Volume = Mass ÷ Density. Enter any two values in the calculator above to find the third.
The SI unit of density is kilogram per cubic metre (kg/m³). In chemistry and school labs, g/cm³ (or g/mL) is also very common because the numbers are easier to work with.
Multiply the value in g/cm³ by 1,000 to get kg/m³. For example, 2.7 g/cm³ × 1,000 = 2,700 kg/m³. To go the other way, divide by 1,000.
Water has a density of about 1 g/cm³, which is 1,000 kg/m³ (at roughly 4°C). This is the reference value used to decide whether an object floats or sinks.
Compare the object's density with the liquid's density. If the object is less dense than the liquid, it floats; if it is denser, it sinks. For water, that means below 1 g/cm³ floats and above 1 g/cm³ sinks.
Yes. One millilitre is exactly equal to one cubic centimetre, so a density in g/mL has the same number as the same density in g/cm³.
Yes. Density is used across CBSE physics and chemistry, and in NEET and JEE topics like fluids, buoyancy and solutions. The calculator uses the standard SI-based formulas expected in those exams.