Mass Calculator
Calculate mass from density and volume, or from force and acceleration.
Inputs
Mass
1,000.000000
Mass (kg)
1,000.000000
Mass (lb)
2,204.624
Mass (g)
1,000,000.000
Step by step
Density in kg/m³
1000 kg/m³ × 1
= 1000 kg/m³
Volume in m³
1 m³ × 1
= 1 m³
Mass = density × volume
1000 × 1
= 1000 kg = 1000 kg
How it works
Mass can be derived two ways: from its definition as density × volume (useful for objects of known material), or from Newton's second law F = ma (useful when you know the net force and resulting acceleration). Note that mass and weight are different quantities — mass is a measure of inertia, weight is the gravitational force on that mass.
Formulas
Mass from density and volume
Mass = Density × Volume
- m
- Mass (kg)
- ρ
- Density (kg/m³)
- V
- Volume (m³)
Mass from Newton's second law
Mass = Net Force ÷ Acceleration
- m
- Mass (kg)
- F
- Net force (N)
- a
- Acceleration (m/s²)
Frequently Asked Questions
What is the difference between mass and weight?
Mass is the amount of matter in an object (kilograms) and does not change with location. Weight is the force exerted by gravity on that mass (Newtons): W = mg. On the Moon, your mass is the same but your weight is 1/6 that on Earth.
When would I use m = F/a instead of m = ρV?
Use F/a when you measure the force applied to an object and its resulting acceleration — for example, when calibrating a force sensor or solving a physics problem. Use ρV when you know the material and can measure the object's volume.
What is a slug?
A slug is the US customary unit of mass: the mass that accelerates at 1 ft/s² under 1 lbf of force. 1 slug = 14.594 kg. It's rarely used outside engineering dynamics.
1 litre of water weighs how many kg?
Water's density is 1 kg/L at standard conditions, so 1 litre of water has a mass of 1 kg. Enter density=1 kg/L, volume=1 L to verify.