Physics & Force
Calculate the weight force (in newtons) from mass using gravity. Pick your planet.
Weight (Force)
686.70 N
Earth
Weight is the force exerted by gravity on an object's mass. The formula is W = m × g, where m is mass (kg) and g is gravitational acceleration (m/s²).
Weight and mass are often confused but distinct: mass is the amount of matter in an object (constant everywhere), while weight is the gravitational force acting on that mass (varies by location). On Earth, your weight changes based on latitude and altitude; on other planets, the difference is dramatic—you'd weigh only one-sixth as much on the Moon, but over two-and-a-half times more on Jupiter.
The calculator applies the formula W = m × g, where W is weight in newtons, m is your mass in kilograms, and g is the gravitational acceleration on your chosen planet. Earth's gravity is 9.81 m/s², the Moon's is 1.62 m/s², Mars is 3.71 m/s², and Jupiter is 24.79 m/s². The tool also converts the result to kilogram-force (kgf) and pound-force (lbf) for everyday reference.
W = m × g
Where:
— W is weight in newtons (N)
— m is mass in kilograms (kg)
— g is gravitational acceleration (m/s²)The weight force is simply the product of mass and local gravity. A 70 kg person on Earth experiences 70 × 9.81 = 686.7 N of gravitational force downward. On the Moon (g = 1.62 m/s²), that same person would experience only 113.4 N. The result shows weight, not mass—which is why astronauts 'weigh' less on the Moon even though their mass hasn't changed.
| Input | Result | Notes |
|---|---|---|
| 70 kg on Earth (g = 9.81 m/s²) | 686.7 newtons (also 70 kgf or 151.2 lbf) | Standard adult weight on Earth; equivalent to 'I weigh 151 pounds' on a bathroom scale |
| 70 kg on the Moon (g = 1.62 m/s²) | 113.4 newtons (also 11.6 kgf or 25.4 lbf) | Apollo astronauts bounded easily on the Moon because weight was only 16.5% of Earth weight |
| 70 kg on Jupiter (g = 24.79 m/s²) | 1735.3 newtons (also 176.8 kgf or 389.6 lbf) | You'd feel 2.5× heavier; standing or moving would be extremely difficult |
Newtons are the SI unit of force. Weight is a force (gravity pulling on mass), not mass itself. Kilogram is mass. On scales, we label 'kg' as shorthand for kilogram-force (kgf), which is the weight of 1 kg on Earth—but strictly speaking, weight is always in newtons.
Mass is the amount of matter (constant, measured in kg). Weight is gravitational force on that mass (measured in N, varies by location). A 70 kg person has the same mass everywhere, but weighs 686.7 N on Earth, 113.4 N on the Moon, and 1735.3 N on Jupiter.
Jupiter is much more massive and larger than Earth. Gravity depends on both mass and distance from the center—Jupiter's huge mass creates intense gravity at its surface, making it 2.5× stronger than Earth's.
Roughly, yes—but most scales show kg or lb (units of mass/force) for convenience. Technically, a bathroom scale measures normal force (how hard the scale pushes back on you), which equals your weight when standing still on a flat surface.
These are standard values for surface gravity on each planet. Real gravity varies slightly by latitude and altitude on each world; this calculator uses typical, widely-accepted approximations.
Yes—enter any mass (kg) and choose a planet. The formula W = m × g works for any object. This is useful for engineering, physics homework, or imagining how heavy spacecraft or rocks would be in space.