Your weight on Ganymede
A person who weighs 150 pounds on Earth weighs about 22 pounds on Ganymede, because Ganymede's surface gravity is 0.15 g. A person who weighs 70 kilograms on Earth weighs about 10 kilograms on Ganymede.
Illustration computed from Ganymede's measured and derived values, not a photograph.
What it’s like to stand here
Why your weight changes here
Ganymede is the largest moon in the solar system, wider than the planet Mercury, yet you would weigh much less on it: about 15% of your Earth weight, against Mercury's 38%. Size alone does not set gravity. In g = GM/r², Ganymede's radius of about 2,630 kilometres is a little larger than Mercury's, but its mass is less than half of Mercury's, because Ganymede is roughly half ice while Mercury is mostly iron and rock. Less mass at a similar distance from the centre means a weaker pull. Your mass would be the same as at home. Jupiter's gravity would not add to your weight either: Ganymede and everything on it fall around Jupiter together, so only Ganymede's own pull reaches the scale.
Your weight on every world in the solar system
Every body gravityfinder carries, with its gravity relative to Earth’s and what you would weigh there. Type your weight in the calculator above and the table follows it. The four giants have no surface, so theirs is the pull at the cloud tops.
| World | Type | Gravity | Weight (lb) | Weight (kg) |
|---|---|---|---|---|
| Mercury | planet | 0.38× | 56.5 | 25.6 |
| Venus | planet | 0.90× | 136 | 61.6 |
| Earth | planet | 1.00× | 150 | 68 |
| Mars | planet | 0.38× | 56.7 | 25.7 |
| Jupitercloud tops | planet | 2.53× | 379 | 172 |
| Saturncloud tops | planet | 1.07× | 160 | 72.5 |
| Uranuscloud tops | planet | 0.90× | 136 | 61.5 |
| Neptunecloud tops | planet | 1.14× | 171 | 77.5 |
| Ceres | dwarf planet | 0.029× | 4.4 | 2 |
| Pluto | dwarf planet | 0.063× | 9.4 | 4.3 |
| The Moon | moon of Earth | 0.17× | 24.8 | 11.2 |
| Io | moon of Jupiter | 0.18× | 27.5 | 12.5 |
| Europa | moon of Jupiter | 0.13× | 20.1 | 9.1 |
| Ganymede | moon of Jupiter | 0.15× | 21.8 | 9.9 |
| Callisto | moon of Jupiter | 0.13× | 18.9 | 8.6 |
| Titan | moon of Saturn | 0.14× | 20.7 | 9.4 |
| Enceladus | moon of Saturn | 0.012× | 1.7 | 0.8 |
| Triton | moon of Neptune | 0.079× | 11.9 | 5.4 |
| Charon | moon of Pluto | 0.029× | 4.4 | 2 |
Worked example: the formula with Ganymede's numbers
Surface gravity comes from Newton’s law of gravitation: g = G × M ÷ r², where G is the gravitational constant, M the body’s mass and r the distance from its centre to where you stand.
- G = 6.674 × 10⁻¹¹ m³ kg⁻¹ s⁻²
- M = 1.48 × 10²³ kg (Ganymede's mass)
- r = 2,631 km = 2.63 × 10⁶ m (mean radius)
- g = 6.674 × 10⁻¹¹ × 1.48 × 10²³ ÷ (2.63 × 10⁶)² = 1.43 m/s²
Earth, through the same formula, gives 9.82 m/s². So Ganymede pulls 1.43 ÷ 9.82 = 0.145 times as hard as Earth.
Your weight on Ganymede is your Earth weight times that ratio: 150 lb × 0.145 = 21.8 lb, or about 22 pounds.
The exoplanets closest to Ganymede's gravity
No exoplanet gravityfinder states a gravity for comes within 10% of Ganymede's 0.15 g; these are the nearest. Each has a mass and size good enough for gravityfinder to state its surface gravity.
More about being on Ganymede
If your children grew up herea playful thought experiment
Low gravity, 0.15 times Earth's. A child who grew up here could become strikingly tall and lightly built, about 1.5x taller than on Earth: a 5 ft 10 in adult could stand nearer 8 ft 7 in, with long limbs and slender bones.
- Bones
- Light and slender
- With little weight to carry, the growing skeleton lays down far less bone, the way astronauts' bones thin in months of low gravity.
- Heart
- Unhurried
- With less weight pulling blood down toward the feet, the heart has far less work to do.
- Movement
- Bounding and springy
- So little weight means each step would carry the body up and forward in long, floating strides.
A playful thought experiment from this world’s gravity, not a prediction about any real person. No human has ever grown up off Earth, so no one truly knows; the direction (taller in low gravity, shorter and stockier in high) follows how growing bodies respond to weight.
Hear how a voice sounds herea computed acoustic demoEXPERIMENTAL · just for fun
You would hear nothing at all.
With essentially no atmosphere, there is no medium to carry sound. You could shout into someone's helmet from an inch away and they would hear nothing: space is silent.
How long to get there with today’s craftCALCULATED
At the speed of the Parker Solar Probe, the fastest craft ever built, the trip to Ganymede would take about 38 days; a real mission took the Juno probe just under 5 years to reach Jupiter's neighborhood.
See Ganymede's full page for its orbit, size, sky and how to see it.
Common questions
How much would I weigh on Ganymede?
A person who weighs 150 pounds on Earth weighs about 22 pounds on Ganymede, because Ganymede's surface gravity is 0.15 g. A person who weighs 70 kilograms on Earth weighs about 10 kilograms on Ganymede.
What is the gravity on Ganymede?
Ganymede's surface gravity is about 1.43 m/s², 0.145 times Earth's (0.15 g). gravityfinder computes it from Ganymede's mass and radius with g = GM/r².
What is the difference between mass and weight?
Mass is the amount of matter in you, and it is the same everywhere. Weight is the force gravity exerts on that mass. On Ganymede your mass would be unchanged, but a scale would read 0.145 times what it reads on Earth, because gravity there is weaker.
How high could I jump on Ganymede?
About 6.9 times as high as on Earth, because the same push from your legs works against 0.145 times the gravity. A 50 centimetre standing jump on Earth would carry you about 3.4 metres on Ganymede, and you would stay in the air about 6.9 times as long.
Where in the solar system would you weigh the most and the least?
Of the worlds with ground to stand on, you would weigh the most on Earth (1.00 g) and the least on Enceladus (0.012 g), where a person who weighs 150 pounds on Earth would weigh about 1.7 pounds. The strongest pull of all is at Jupiter's cloud tops, 2.53 g, but there is nothing there to stand on.
Which exoplanets have gravity like Ganymede's?
Of the exoplanets gravityfinder states a surface gravity for, Kepler-138 b (0.17 g), K2-138 f (0.19 g), Kepler-176 c (0.20 g) and Kepler-444 b (about 0.23 g) come closest to Ganymede's 0.15 g. None is within 10%, so read these as the nearest, not a match.
Is Ganymede bigger than Mercury?
Yes, a little wider: about 5,260 kilometres across against Mercury's 4,880. But it has less than half of Mercury's mass, because it is roughly half ice, so its gravity is well under half of Mercury's.
How do I calculate my weight on Ganymede?
Multiply your Earth weight by 0.145, Ganymede's gravity relative to Earth's. For 150 pounds that is 150 × 0.145 = about 22 pounds. The 0.145 comes from g = GM/r² with Ganymede's mass and radius, divided by the same calculation for Earth.
Gravity computed by gravityfinder from Ganymede's mass and radius in the NASA planetary fact sheets (gravity = mass ÷ radius², with Earth = 1). Measured mass.