Mass Calculator
Calculate mass from density and volume, or from weight (force) and gravitational acceleration.
How to use the Mass Calculator
- Enter your inputs into the Mass Calculator above.
- Results update instantly as you type — no submit button needed.
- Adjust any value to see how the result changes in real time.
The mass formulas
m = ρ × V · · · m = W / g
From density and volume directly. From weight (a force), divide by gravitational acceleration (9.81 m/s² on Earth, 1.62 m/s² on the Moon).
Worked example
A 200 cm³ piece of aluminum (ρ = 2.7 g/cm³): m = 200 × 2.7 = 540 g. A person weighing 700 N on Earth (W = mg): mass = 700/9.81 ≈ 71.4 kg. Same person on the Moon: weight 116 N, mass still 71.4 kg.
Frequently asked questions
What's the difference between mass and weight?
Mass is the amount of matter (kg). Weight is the gravitational force on mass (N or lb-force). Mass is constant; weight changes with gravity (less on the Moon).
Why is mass measured in kg, not pounds?
The pound is technically a unit of force (weight) in physics, though commonly used for mass colloquially. The SI unit for mass is the kilogram; the pound-mass (lbm) is the imperial equivalent.
Are mass and gravity related?
Mass creates gravitational attraction. Earth's mass creates the 9.81 m/s² we experience as gravity at its surface. The Moon is less massive, so less surface gravity.