Physics Tools
Mass Calculator
Calculate mass from density and volume, or from weight and gravitational acceleration. Two methods, one result.
kg/m³
m³
Mass
50.00 kg
Weight Equivalent490.50 N
Formulam = ρ × V
MethodDensity & Volume
Physics Tools
Calculate mass from density and volume, or from weight and gravitational acceleration. Two methods, one result.
kg/m³
m³
Mass
50.00 kg
Mass is the amount of matter in an object, measured in kilograms (kg). It differs from weight: mass is constant, while weight depends on gravity. You can calculate mass if you know density and volume, or if you know the weight force and the gravitational acceleration at your location.
Choose a calculation method: Density & Volume or Weight & Gravity. For density mode, enter the material's density (e.g., water is 1000 kg/m³) and the volume. For weight mode, enter the weight force in Newtons and the local gravity. The calculator applies the correct formula and displays mass instantly.
Method 1: m = ρ × V (density times volume). Method 2: m = W / g (weight divided by gravity).In the first method, mass equals density multiplied by volume. Density is mass per unit volume; multiply by volume to get total mass. In the second method, weight is the force caused by gravity pulling on mass; divide weight by gravitational acceleration to recover the original mass.
| Input | Result | Notes |
|---|---|---|
| Density 1000 kg/m³, Volume 0.05 m³ | 50 kg | m = 1000 × 0.05 = 50 kg (like water in a 50 liter tank) |
| Weight 490.5 N, Gravity 9.81 m/s² | 50 kg | m = 490.5 / 9.81 = 50 kg (object weighs 490.5 N on Earth) |
| Density 7850 kg/m³ (steel), Volume 0.001 m³ | 7.85 kg | m = 7850 × 0.001 = 7.85 kg (a steel cube ~10 cm on each side) |
Mass is the amount of matter (constant everywhere), measured in kg. Weight is the force of gravity acting on mass, measured in Newtons. Weight = mass × gravity. On the Moon, your mass stays the same but your weight is much less.
Both methods calculate the same mass if your inputs are correct. Use density & volume for materials or containers, and use weight & gravity when you know the gravitational force.
Density is mass per unit volume. Water is 1000 kg/m³ (1 cubic meter of water weighs 1000 kg). Steel is denser (~7850 kg/m³), wood is less dense (~600 kg/m³).
Weight in pounds is not a mass or force unit in the SI system. Convert pounds-force (lbf) to Newtons: 1 lbf ≈ 4.448 N. Or convert mass in pounds to kg (1 lb ≈ 0.453 kg), then multiply by gravity (9.81 m/s²).
Yes. Use the Weight & Gravity method and enter the local gravity value. Earth is 9.81 m/s², the Moon is ~1.62 m/s², Mars is ~3.71 m/s².
The dash means the calculation cannot be completed. Check that all values are positive numbers, gravity is positive (not zero), and there are no invalid characters in the input fields.