Mass to Weight Calculator
Convert mass to weight (force) on Earth or other planets.
Assumptions used in this calculation
- Standard surface gravity values: Uses published mean surface gravitational acceleration for each body (9.80665 m/s² for Earth), not adjusted for altitude, latitude or local geological variation.
- Point-mass gravity: Treats the object as resting on the planet's surface under uniform gravity, ignoring altitude above the surface or orbital effects.
About this calculator
It's easy to conflate mass and weight in everyday speech, but they're physically different quantities, mass is a fixed amount of matter measured in kilograms, while weight is the force gravity exerts on that mass, and it changes depending on where you are, something that becomes obvious the moment you consider astronauts feeling weightless while their mass stays exactly the same. This calculator takes a mass in kilograms and multiplies it by the local surface gravitational acceleration of Earth or another planet or moon in our solar system to compute the resulting weight in newtons, the correct SI unit of force, alongside the more familiar kilogram-force figure. It's built for anyone curious what they'd weigh on Mars or the Moon, students working through mechanics problems that require distinguishing mass from weight, or engineers needing a quick force figure for a known mass under a specific gravitational field, without looking up each planet's gravity constant separately.
Worked example
70 kg on Earth
Result: 686.7 N (70 kgf)
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