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What If Earth's Gravity Doubled?
Short answer: you’d weigh twice as much, and the same standing jump would reach about half the height, since jump height scales as 1/g. Your mass wouldn’t change at all. Slide g up or down below.
What does a stronger g do to your weight and a standing jump?
Mass is not weight. Mass is how much of you there is; weight is how hard the ground has to push up to keep that mass from accelerating. Standard gravity is 9.80665 m/s². Multiply it and the bathroom scales move even though you have not. A standing jump is a small energy budget converted into height against g, so the same takeoff kinetic energy reaches a height that scales as 1/g. Double g, and that hop is about half as high — if muscles still deliver the same energy, which in a real body they would not, because they now have to lift heavier limbs. The first part is straightforward physics; the second is biology that is not modelled here. It will not claim you could or could not stand up. It will tell you the new newtons.
Written and checked by Aivora Digital · Last updated:
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Results update as you move the controls.
1 is Earth today; 2 is double g.
Typical untrained standing jump is around 0.3–0.4 m.
Your result
150 kgf
apparent weight at 2 g
1,471 N
- Weight now (1 g)
- 735 N
- Weight at this g
- 1,471 N
- Standing jump now
- 0.35 m
- Standing jump at this g
- 0.18 m
- g in this run
- 19.613 m/s²
75 kgf
150 kgf
What does that mean?
A 75 kg body weighs 735 N today and 1,471 N at 2 g — the scales, if they still pretended to show kilograms, would read 150 kg. The same takeoff energy that reaches 0.35 m on Earth reaches 0.18 m here. Stairs, chairs and tree branches all get a new opinion of you; this page only did mg and v²/2g.
At a glance
- Jump on Earth0.35 m
- Jump at this g0.18 m
Compare
| 1 g | 75 kgf / 0.35 m jump |
|---|---|
| 2 g | 150 kgf / 0.18 m |
Compare scenarios
Weight is just mg
Your mass in kilograms times the local acceleration gives newtons, which consumer scales then divide by the old g so they can print a 'kilogram' that is really a force. In 2 g that display would lie unless it was a true mass measurement. This experiment reports both the force in newtons and the equivalent kilograms-force so the comparison is readable. Nothing about diet or bone density is implied. Those are real topics with real literature; they are not computed here.
Jumps shrink as 1/g
Take off with speed v and you rise v² / 2g if drag is ignored. Hold v fixed — same muscle energy into the same legs — and height falls as 1/g. At zero g the formula misbehaves: there is no downward acceleration in this model, so 'jump height' stops meaning a returning hop. At 3 g a 35 cm standing jump becomes about 12 cm. Birds, trees and raindrops would all rewrite their numbers. Only the hop is calculated.
The planet has other opinions
True 2 g on Earth would mean more mass, a smaller radius, or both. Atmosphere scale height, orbital speed, and the habitability of the surface would change with that structural choice. This experiment isolates g as a slider because the question people actually type is about weight and jumping. For radius-and-density knobs, use the twice-as-large experiment. For g going to zero, use the gravity-stopped page, which is a different thought experiment entirely.
Common questions
How much would I weigh if gravity doubled?
Twice as much. Your mass stays the same, but weight is mass times gravity, so the force on the scales doubles.
How high could I jump with double gravity?
About half as high, if your legs delivered the same energy, because jump height scales as 1/g. At 3 g a 35 cm standing jump becomes about 12 cm.
How we calculated this
Weight is mass × gn × the chosen multiple, with gn from NIST / ISO 80000-3. Jump height is the input standing jump divided by the multiple, i.e. constant takeoff energy and no drag. If the multiple is zero, no jump height is shown, because the jump would never come down. Compare rows show 1 g against the chosen g. No musculoskeletal model, no atmosphere, no planetary-structure solve.
Assumptions and limitations
This is a simplified estimate. Actual results depend on factors the model does not include.
This is a simplified thought experiment. It uses transparent assumptions so you can see what changes — it is not a full physical simulation of the real world.
- Takeoff kinetic energy is independent of g (optimistic for muscles).
- Air resistance is ignored.
- gn is 9.80665 m/s² regardless of latitude.
- Mass does not change; only weight does.
- Planetary radius and atmosphere are not adjusted here.
Sources
- NIST CODATA — standard acceleration of gravity
gn = 9.80665 m/s², the conventional standard gravity (also ISO 80000-3).
- NASA Earth fact sheet
Mass, radius, rotation period and orbital speed used as the baseline Earth.
Go further
Related experiments that pick up where this one leaves off.
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