Density Calculator
Choose what to solve for: density, mass or volume. Then choose your units: grams and cm³, kilograms and m³, or pounds and ft³. Enter the other two values and press Calculate. Every value has to be above 0. The answer shows 6 decimal places, and the line below it gives the same quantity in the other two sets of units.
How to use the Density Calculator
- Enter your numbers in the Density Calculator above.
- Press the Calculate button to see the result.
- To try other numbers, change any value and press the button again.
The density equation
ρ = m / V · · · m = ρ × V · · · V = m / ρ
ρ is density, m is mass and V is volume. Each set of units belongs together: grams with cm³ give g/cm³, kilograms with m³ give kg/m³, and pounds with ft³ give lb/ft³. The conversions use the exact definitions 1 lb = 0.45359237 kg and 1 ft = 0.3048 m, so 1 lb/ft³ = 16.018463 kg/m³ and 1 g/cm³ = 62.427961 lb/ft³.
Worked example
A 250 g block measuring 5 cm × 4 cm × 2 cm has a volume of 40 cm³. Solve for density with a mass of 250 and a volume of 40, and the calculator shows 6.250000 g/cm³. Solve for volume with a mass of 250 and a density of 6.25, and you get 40.000000 cm³ back. The line below the density gives 6,250 kg/m³ and 390.174754 lb/ft³. In pounds, 250 lb in 4 ft³ is 62.500000 lb/ft³, the same as 1.001154 g/cm³.
Frequently asked questions
Which units does the calculator use?
Pick one of three sets: grams, cm³ and g/cm³; kilograms, m³ and kg/m³; or pounds, ft³ and lb/ft³. All fields use the set you pick, and the line below the answer converts it to the other two. 1 g/cm³ is 1,000 kg/m³. To mix units, such as a density in lb/ft³ with a volume in liters, use the mass calculator.
How do I convert g/cm³ or kg/m³ to lb/ft³?
Multiply g/cm³ by 62.427961, or divide kg/m³ by 16.018463. Solve for density with any mass and volume in the units you have, and the line below the answer shows lb/ft³. The factors come from 1 lb = 0.45359237 kg and 1 ft = 0.3048 m.
How do I find the volume of an irregular object?
Use water displacement. Read the water level in a graduated cylinder, sink the object and read it again. The rise is the object's volume, and 1 mL is 1 cm³. Weigh the object, then enter its mass and that volume.
Why do the values have to be above 0?
A mass, volume or density of 0 or less gives no physical answer, and solving for density or volume divides by one of them. The calculator shows a message instead of a result.