Your weight isn't a fixed property of your body — it's the force gravity exerts on your mass, and that force changes depending on where you're standing. This calculator takes your Earth weight and scales it by each body's surface gravity, so you can see exactly how much you'd weigh on the Moon, Mars, or any other planet in the solar system.
How the calculator works
Every body has its own surface gravity, determined by its mass and radius. The calculator expresses each body's surface gravity as a ratio to Earth's (Earth = 1.0×) and multiplies that ratio by your Earth weight: weight_body = earthWeight × (g_body / g_earth). Because it's a simple ratio, the unit you enter — pounds or kilograms — carries straight through to the result without any conversion step.
The gravity ratios used here are the standard published surface-gravity values relative to Earth's 9.8 m/s², rounded to three decimal places: Mercury 0.377×, Venus 0.905×, Earth 1.000×, the Moon 0.166×, Mars 0.377×, Jupiter 2.528×, Saturn 1.065×, Uranus 0.886×, Neptune 1.137×, Pluto 0.063×, and the Sun 27.9×.
Why weight changes but mass doesn't
Mass measures how much matter you're made of, and it's the same number no matter where you are — on Earth, floating in orbit, or standing on Mars. Weight, on the other hand, is a force: it's your mass multiplied by the local gravitational acceleration. Because different bodies pull with different strength, the same mass produces a different weight on each one. A 150 lb person doesn't become lighter or heavier as a person when they travel to the Moon — they simply experience less gravitational force, so a bathroom scale there would read about 25 lb.
Limits and things to keep in mind
This calculator uses each body's average surface gravity, but real surface gravity varies slightly by location and altitude — Mars and the Moon both have small regional variations. Gas giants like Jupiter and Saturn don't have a solid surface at all; the gravity ratio here refers to the gravitational acceleration at their visible cloud-top layer, the closest analogue to a "surface." The Sun's ratio (27.9×) is a theoretical figure since no one could survive standing on it, but the math works the same way. For anything beyond curiosity or classroom use — like spacecraft engineering or life-support planning — consult mission-specific planetary data.