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Weight on Other Planets Calculator

Gravity varies dramatically across the Solar System, meaning your weight would shift dramatically if you stepped onto another world. Jupiter's intense gravitational pull would make you feel nearly 2.5 times heavier, while on Mars you'd weigh just over one-third of your Earth weight. This calculator uses gravitational acceleration ratios to show what the scale would read on each major planet and moon, helping space enthusiasts and students understand how celestial mechanics affects our bodies.

Last updated:

Creators Dominik Czernia, PhD
2,917 people find this calculator helpful

The Weight Conversion Formula

Planetary weight depends on the surface gravity of each celestial body relative to Earth. The relationship is straightforward: multiply your Earth weight by the gravitational factor specific to each world.

Weight on Planet = Earth Weight × (g_planet ÷ g_Earth)

Or simply: Weight on Planet = Earth Weight × Gravity Factor

Where gravity factors are:

Mercury: 0.38 | Venus: 0.91 | Mars: 0.38

Jupiter: 2.34 | Saturn: 1.06 | Uranus: 0.92

Neptune: 1.19 | Pluto: 0.06 | Moon: 0.167

Ganymede: 0.146

  • Earth Weight — Your measured weight in kilograms or pounds on Earth's surface
  • g_planet — Gravitational acceleration at the surface of the target celestial body
  • g_Earth — Standard gravitational acceleration on Earth: 9.81 m/s²
  • Gravity Factor — Pre-calculated ratio of a planet's surface gravity to Earth's gravity

Understanding Gravity Across Worlds

Gravity strength depends on two factors: an object's mass and your distance from its centre. Larger, denser bodies pull harder, while being further away weakens the pull. Earth's surface gravity—9.81 m/s²—serves as the baseline.

The gas giants Jupiter and Saturn have enormous masses but extremely low-density atmospheres. If you could somehow stand on Jupiter's cloud tops, you'd experience 2.34 times Earth's gravity. Saturn, despite being larger, is less dense and pulls with only 1.06 times Earth's force.

Smaller, denser terrestrial planets like Mercury and Mars have surface gravities much weaker than Earth's. Mercury's weak gravity (0.38g) results from its small size. The Moon, only one-sixth of Earth's width, gives you just 16.7% of your Earth weight—perfect for those Apollo astronaut bounces we've all seen.

Mass Versus Weight: A Critical Distinction

Mass is intrinsic and invariant. The amount of matter composing your body remains constant whether you're on Earth, Mars, or drifting in deep space. It's a fundamental property measured in kilograms.

Weight is the force gravity exerts on your mass. It changes whenever gravitational acceleration changes. In zero gravity, far from any celestial body, your weight would be zero—but your mass persists unchanged.

This distinction matters for space missions. A spacecraft's fuel requirements depend on an object's mass, not weight. But a landing module's structural stress depends on weight at the landing site. Astronauts training for Mars must account for both considerations: their mass determines inertia and resource needs, while Mars's lower gravity means their effective weight during surface operations.

Practical Considerations for Planetary Weights

Several real-world factors complicate the straightforward calculation.

  1. Most Planets Lack Solid Surfaces — Jupiter, Saturn, Uranus, and Neptune are gas giants with no solid ground beneath their atmospheres. Gravity values are defined at the cloud-top level, making true 'weight on the surface' impossible. Any structure would sink indefinitely into the dense fluid.
  2. Earth's Position Affects Your Weight — You weigh roughly 1% more at the poles than the equator. This occurs partly because poles are slightly closer to Earth's centre, but mainly because rotational centrifugal force at the equator counteracts gravity. When using this calculator, use your weight measured at your local latitude for greatest accuracy.
  3. Altitude Significantly Changes Gravity — The calculator assumes sea-level or reference-level measurements. On Earth, you weigh slightly less on a mountain than in a valley. On other worlds, standing on a tall volcano or in a deep crater alters gravity noticeably, particularly on smaller bodies like the Moon or asteroids.
  4. Different Planets Have Non-Uniform Gravity — Some planets rotate rapidly (Jupiter completes a day in 10 hours), creating stronger centrifugal effects. Irregular mass distributions and internal structures also create gravity variations across a single world's surface, similar to Earth's 1% polar-to-equator difference.

Real-World Applications and Why This Matters

Understanding planetary gravity isn't purely academic. Mission planners use these ratios to calculate fuel requirements, structural loads, and equipment feasibility. A vehicle that works on Mars might fail catastrophically on Jupiter if engineers haven't accounted for the 6-fold difference in weight.

Physiologists studying long-term human spaceflight consider gravity's effects on bone density, muscle atrophy, and cardiovascular function. Low-gravity environments like the Moon (0.167g) produce measurable bone loss in months. Future Mars colonists would face significant readaptation challenges returning to Earth's full gravity.

For educational purposes, calculating personal weights across the Solar System builds intuition about gravitational physics. A person weighing 70 kg on Earth would weigh just 26 kg on Mars—light enough to leap five times higher with the same muscle effort—but would crush beneath their own weight at 164 kg on Jupiter.

Frequently Asked Questions

If I weigh 70 kg on Earth, what would I weigh on Mars?

Your Martian weight would be approximately 26.6 kg. Mars has a surface gravity of 3.73 m/s², compared to Earth's 9.81 m/s², giving it a gravity factor of 0.38. Simply multiply your Earth weight by this factor: 70 × 0.38 = 26.6 kg. This dramatic reduction stems from Mars being smaller and less dense than Earth. Interestingly, Mercury has identical surface gravity to Mars despite being closer to the Sun, so you'd weigh the same on both planets.

Why would I weigh more on Saturn than Mars even though Saturn is bigger?

Saturn is indeed larger than Earth, but its average density is extraordinarily low—lower than water. Its mass is only 95 times Earth's, whereas Jupiter is 318 times Earth's mass. You'd weigh 1.06 times your Earth weight on Saturn's cloud tops, barely heavier than on Earth. Size alone doesn't determine surface gravity; mass and density matter equally. A planet could be enormous but so diffuse that its gravity remains weak.

Is the Moon's gravity really one-sixth of Earth's?

Yes, approximately. The Moon has a surface gravity of 1.62 m/s² versus Earth's 9.81 m/s², yielding a factor of 0.167 (roughly one-sixth). This is why Apollo astronauts appeared to bounce effortlessly across the lunar surface in their spacesuits. A 70 kg person would weigh only 11.7 kg on the Moon. The Moon's small mass and radius both contribute to this weak gravity, making it easier for spacecraft to land and launch.

How does Earth's rotation affect my weight compared to other planets?

Earth's rotation is relatively slow—one complete rotation every 24 hours. This creates a centrifugal effect strongest at the equator, reducing your apparent weight by roughly 0.3%. Jupiter, by contrast, rotates once every 10 hours, producing much stronger centrifugal forces that slightly reduce gravity readings. Other planets rotate at intermediate rates. These rotational effects are minor compared to the fundamental differences in planetary mass, but they become significant on rapidly spinning worlds.

Could humans survive on Jupiter if it had a solid surface?

Unlikely. At 2.34 times Earth's gravity, a 70 kg person would feel as though they weigh 164 kg. Your heart would struggle to pump blood upward against such force. Your legs would bear crushing loads with each step. Over time, extended exposure to 2.34g would cause severe physiological stress: bone strength inadequate for support, cardiovascular strain, and likely organ damage. Jupiter's surface would be lethal not just from extreme gravity and radiation, but also from its hostile atmospheric composition.

Does my mass change when I travel to another planet?

Never. Mass is an intrinsic property of matter independent of location. Your mass measured on Earth remains identical whether you're on Mars, the Moon, or in the vacuum of space. What changes is your weight—the force exerted by gravity on that constant mass. This distinction is crucial for spacecraft design: fuel mass calculations depend on your body's mass, while structural loads depend on weight at each destination. An astronaut's 75 kg mass never changes; their weight drops to 28.5 kg on Mars.

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