Planetary Weight Calculator
Compare your Earth weight with your weight on planets, moons, and other bodies using surface gravity and simple conversion formulas.
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Compare your Earth weight with your weight on planets, moons, and other bodies using surface gravity and simple conversion formulas.
Tell us more, and we'll get back to you.
Contact UsCompare your Earth weight with your weight on planets, moons, and other bodies using surface gravity and simple conversion formulas.
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One of the most fundamental yet commonly misunderstood concepts in physics is the difference between mass and weight. While we often use these terms interchangeably in everyday conversation, they represent distinct physical properties that behave differently as we move from planet to planet or into the depths of space.
Mass is an intrinsic property of matter that measures the amount of material in an object. It remains constant regardless of location - whether you're standing on Earth, floating on the International Space Station, or standing on the surface of Mars. Mass is what gives an object inertia, its resistance to changes in motion. It's typically measured in kilograms (kg) in the metric system.
Weight, however, is the force exerted on an object due to gravity. It's calculated as the product of mass and the local gravitational field strength (W = m × g). Unlike mass, weight varies depending on the gravitational pull of the celestial body you're on. This is why astronauts appear "weightless" in orbit despite retaining their full mass - they're in continuous free fall around Earth, experiencing apparent weightlessness. Weight is measured in newtons (N) in the metric system, though we commonly express it in mass units (kg or lbs) in everyday contexts.
Weight (N) = Mass (kg) × Local gravity (m/s²)
The strength of a planet's gravitational field depends on several factors, primarily its mass and radius. According to Newton's Law of Universal Gravitation, the gravitational force between two objects is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers.
F = G × (M × m) / r²
Where:
F = Gravitational force
G = Gravitational constant
M = Mass of planet
m = Mass of object
r = Distance between centers
g = G × M / r²
This gives us the acceleration due to gravity at a planet's surface. On Earth, this value is approximately 9.8 m/s² (often rounded to 10 m/s² for simple calculations), which we define as 1g.
Our solar system presents a fascinating range of gravitational environments. The gas giants like Jupiter exert powerful gravitational pulls due to their enormous mass, while smaller bodies like Mercury or Pluto have much weaker gravitational fields. These variations create dramatically different weight experiences for the same mass across different worlds.
| Celestial Body | Mass (Earth = 1) | Radius (Earth = 1) | Surface Gravity (g) | Weight Comparison |
|---|---|---|---|---|
| Mercury | 0.055 | 0.383 | 0.38 | A 70kg person weighs 260N |
| Venus | 0.815 | 0.949 | 0.91 | A 70kg person weighs 624N |
| Earth | 1.000 | 1.000 | 1.00 | A 70kg person weighs 686N |
| Moon | 0.012 | 0.273 | 0.17 | A 70kg person weighs 114N |
| Mars | 0.107 | 0.532 | 0.38 | A 70kg person weighs 260N |
| Jupiter | 317.8 | 11.209 | 2.53 | A 70kg person weighs 1735N |
| Saturn | 95.2 | 9.449 | 1.07 | A 70kg person weighs 734N |
| Uranus | 14.5 | 4.007 | 0.92 | A 70kg person weighs 631N |
| Neptune | 17.1 | 3.883 | 1.12 | A 70kg person weighs 768N |
| Pluto | 0.002 | 0.186 | 0.06 | A 70kg person weighs 41N |
Engineers must calculate precise gravitational influences for orbital trajectories and landing procedures
Escaping a planet's gravitational pull requires specific amounts of fuel based on the local gravity
Different landing gear and parachute designs are needed based on destination gravity
Using a planet's gravity as a slingshot to propel spacecraft to distant targets
Astronauts lose 1-2% bone mass per month in microgravity environments
Reduced gravity leads to muscle weakening without resistance training
Blood redistribution occurs as gravity no longer pulls fluids downward
Inner ear and proprioception systems must adapt to new gravitational environments
As humanity contemplates establishing permanent settlements beyond Earth, understanding and adapting to different gravitational environments becomes essential for long-term survival. From the low gravity of the Moon to the crushing pressure of Jupiter's gravitational field, each destination presents unique challenges and opportunities.
Scientists continue to debate what minimum level of gravity is necessary for long-term human health. Studies suggest several critical thresholds:
Approximately 0.38g (Mars gravity) may be sufficient to prevent severe bone loss
Unknown, but researchers believe at least 0.5g might be needed for proper fetal development
Approximately 0.8g, though this can be supplemented with resistance training
Rotating habitats would need specific diameters and rotation rates to simulate Earth gravity without causing disorientation
Beyond the familiar planets of our solar system lie even more extreme gravitational environments that challenge our understanding of physics and the limits of matter. These cosmic heavyweights create gravitational conditions that would be instantly fatal to humans and destructive to most materials.
| Object Type | Example | Surface Gravity | Effect on 70kg Human |
|---|---|---|---|
| Neutron Star | PSR J0348+0432 | ~200 billion g | Instantly crushed to subatomic particles |
| White Dwarf | Sirius B | ~350,000g | Compressed to thickness of paper |
| Super-Earth | Kepler-20b | ~2-3g | Weight would be 140-210kg |
| Black Hole | Sagittarius A* | Infinite at event horizon | Spaghettification from tidal forces |
Near black holes, the extreme gravitational gradient creates tidal forces so powerful they can stretch matter into long, thin strands - a process colorfully termed "spaghettification" by physicists. These environments help test the limits of our physical theories, particularly general relativity.
For long-duration space missions or permanent habitats in low-gravity environments, scientists have proposed various methods to simulate Earth-like gravity. These approaches could help mitigate the negative health effects associated with extended exposure to microgravity or low gravity.
Large wheel-shaped structures that create artificial gravity through rotation
Two modules connected by a cable rotating around a common center of mass
Personal devices for periodic exposure to higher g-forces
a = ω²r
Where:
a = artificial gravity
ω = angular velocity
r = radius
Using strong magnetic fields to simulate downward force (theoretical)
Pressure suits that create resistance similar to gravitational force
Specialized equipment providing gravitational loads during exercise
Medications to counter bone loss and muscle atrophy (under development)
The most promising near-term solution is the rotating habitat concept, first popularized by physicist Wernher von Braun and later elaborated in designs such as the Stanford Torus and O'Neill Cylinder. These structures would need to be several hundred meters in diameter to minimize the Coriolis effect, which could otherwise cause disorientation and motion sickness.
With over 5,000 exoplanets confirmed as of 2025, astronomers are discovering worlds with gravitational conditions unlike anything in our solar system. These range from super-Earths with gravity up to 3 times that of Earth to extremely low-gravity environments on small, rocky worlds.
A "Super-Earth" where a 70kg person would weigh over 200kg
An "Ultra-hot Jupiter" where iron literally rains from the sky under intense gravity
Seven Earth-sized planets with gravity ranging from 0.6g to 1.13g
A gas giant where silicate (glass) particles rain sideways in 5,400 mph winds under 21.2 times Earth's gravity
As exoplanet detection techniques improve, we're beginning to identify potentially habitable worlds with gravity similar to Earth's. These "Goldilocks" planets represent the most promising targets for future interstellar exploration, as they would require minimal adaptation for human physiology.
Use the planetary weight calculator as a working estimate for how weight changes under different surface gravity values. It gives you a clean number from the values you enter, but the answer is only as good as those inputs. Small entry mistakes can look like big changes when the formula uses ratios, logs, or repeated conversions, so the first job is to make sure the starting values describe the same situation.
Start with your Earth weight and the unit you normally use. Write those values down before you change anything. If you come back later and cannot remember what you entered, the result is hard to check and easy to misread. A quick note beside the calculation often saves more time than another round of guessing.
The main result is your equivalent weight on each selected planet, moon, or small body. Read it together with the inputs, not as a standalone truth. A number with no context can be technically correct and still point you toward a poor decision if the starting assumptions were too broad or came from a different source.
Your mass stays the same, but the force of gravity changes. The displayed weight uses familiar Earth weight units for comparison. This matters because unit mismatches are quiet. The calculator will still return a number, but it may be answering a different question than the one you meant to ask.
For a quick check, use a simple example: A 180 lb person would weigh far less on the Moon and much more under Jupiter gravity. A rough mental estimate like that helps catch decimal slips, unit mix-ups, and copied values that landed in the wrong field. It does not have to be exact. It only needs to be close enough to flag an answer that makes no sense.
A common mistake is assuming low weight means the body itself has less mass. When the result looks odd, check that first. Most surprising answers come from a plain input problem rather than from the math itself. If the inputs pass that first check, then look at units, rounding, and whether you selected the right mode.
Change one input at a time when you are exploring options. If you change several fields together, you may not know which one moved the result. A calculator is more useful when it helps you see cause and effect, and that only happens when the comparison is controlled.
Keep a copy of the first result before testing another scenario. That makes comparisons easier and keeps you from chasing a moving target. If the second result is better, you can explain why. If it is worse, you can go back to the earlier assumption without rebuilding the whole calculation.
Surface gravity depends on both mass and radius, so a large planet is not always the simple answer people expect. Those outside factors do not make the calculator useless. They explain why the answer should be treated as an estimate until it is checked against direct measurement, professional guidance, or real-world results.
The calculator cannot know terrain, rotation, altitude, spacecraft motion, or the fact that gas giants do not have a solid surface to stand on. Those details may matter in real life, so treat the answer as a starting point for judgment rather than the end of the work. The cleaner the inputs, the more useful the estimate, but the estimate still has boundaries.
For repeat use, record the Earth weight entered, unit, selected body, and whether you are comparing weight or force in newtons. A short note is enough. You do not need a perfect log, but you do need enough detail to recreate the calculation later. That habit is especially helpful when you are comparing several days, properties, samples, products, or plans.
Try a second scenario when the input is uncertain: compare the Moon, Mars, and Earth if you want a quick feel for crewed exploration environments. The gap between the two answers is often more useful than either single answer by itself. A narrow gap means the estimate is stable. A wide gap tells you which input deserves better data.
Round the result to match the decision. Extra decimal places can make an estimate look more exact than it is. Use more precision for lab work, engineering notes, or financial records, and less for everyday planning. A rounded number that is honest about uncertainty is better than a long number with false confidence.
If you share the result with someone else, include the inputs and units. The answer alone can be misunderstood, especially when two people use different conventions or reference points. A shared result should say what was entered, what unit was used, and what assumption would change the answer first.
Use plain language beside the number. A note such as "based on the current estimate" or "assuming the entered values are correct" keeps the result from sounding more certain than it is. That wording is useful when the result will be copied into a plan, message, report, or checklist.
Look for outside constraints before acting. Time, budget, safety rules, medical guidance, local codes, equipment limits, and data quality can all matter more than a tidy calculation. The calculator can narrow the question, but it cannot remove every constraint around the decision.
Be careful with mission design, health planning, or equipment loads. In those cases, use the calculator for preparation and discussion, then rely on a qualified professional, official source, direct measurement, or written standard for the final call. That is not a weakness in the calculator. It is a normal part of using estimates responsibly.
When comparing two results, ask whether the difference is large enough to matter. A tiny change may be noise, rounding, or normal variation. A large change deserves a closer look at the input that caused it. The practical question is usually not whether two numbers differ, but whether that difference changes what you would do next.
If the calculator supports several modes, choose the mode that matches your question. Do not force a problem into the nearest-looking formula just because the fields are available. If the mode feels awkward, step back and write the question in one sentence before entering values.
Check the scale of the answer. A result that is ten times higher or lower than expected usually means a unit, decimal, or reference point deserves another look. Scale checks are quick, and they catch many errors before they turn into bad plans.
Save the assumptions that went into the calculation. Future you will care less about the exact button clicks and more about why those numbers made sense at the time. This is especially true when prices, schedules, measurements, or health details change over time.
A good calculator result should make the next step clearer. It might tell you what to measure again, which scenario to compare, or which question to take to a professional. If the result leaves you more confused, simplify the inputs and run a smaller version of the problem.
Use ranges when the input is a guess. Enter a low estimate, a middle estimate, and a high estimate. If all three answers point in the same direction, you can be more comfortable with the conclusion. If they point in different directions, the input needs better evidence before the result should guide action.
Keep the result close to the task at hand. The planetary weight calculator answers a specific question about how weight changes under different surface gravity values. It should not be stretched into a promise about outcomes, safety, profit, health, performance, or future behavior. Good use means knowing what the calculation can answer and what still needs human review.
Mass is a measure of the amount of matter in an object and remains constant regardless of location. Weight, on the other hand, is the force exerted on that mass due to gravity and varies depending on the gravitational field strength. For example, a person with a mass of 70 kg will have that same mass anywhere in the universe, but their weight will be different on each planet - approximately 686 newtons (N) on Earth but only about 114 N on the Moon. Mass is measured in kilograms (kg), while weight is properly measured in newtons (N), though in everyday language we often express weight using mass units.
We weigh less on the Moon because the Moon has less mass than Earth and thus a weaker gravitational field. The Moon's gravitational pull is approximately 1/6 (or about 16.6%) of Earth's gravity. This means that if you weigh 100 kg on Earth, you would weigh only about 16.6 kg on the Moon. The reduced gravity is why astronauts could bounce and jump so high during the Apollo missions - their muscles, evolved for Earth's gravity, were much stronger than needed for the Moon's weaker gravitational pull.
Among the planets in our solar system, you would weigh the most on Jupiter, which has the strongest gravitational pull at its cloud tops - about 2.53 times Earth's gravity. A person weighing 70 kg (686 N) on Earth would weigh about 177 kg (1,735 N) on Jupiter. However, Jupiter is a gas giant with no solid surface, so you couldn't actually stand on it. Among planets with solid surfaces, you would weigh the most on Neptune, where the gravity is about 1.12 times Earth's gravity, resulting in about 12% more weight than on Earth.
No, your mass would not change if you traveled to Mars or any other planet. Mass is an intrinsic property of matter that remains constant regardless of location. What would change is your weight, which is the force exerted on your mass by gravity. Mars has about 38% of Earth's gravity, so if your mass is 70 kg, your weight would be about 260 N on Mars compared to 686 N on Earth. The different feeling of "heaviness" or "lightness" you would experience on different planets is due to these changes in weight, not mass.
Planetary gravity is calculated using Newton's Law of Universal Gravitation. The gravitational acceleration (g) at a planet's surface is determined by the formula g = G × M / r², where G is the gravitational constant (6.67 × 10^-11 N·m²/kg²), M is the mass of the planet in kilograms, and r is the radius of the planet in meters. This explains why massive planets like Jupiter have stronger gravity despite their larger size - the increase in mass more than compensates for the increased radius. Earth's gravity is approximately 9.81 m/s², which we often round to 10 m/s² for simple calculations.
Pluto's gravity is only about 6% of Earth's (0.06g) due to its small size and low mass. Pluto has a diameter of approximately 2,377 km (about 18% of Earth's) and a mass of only about 0.2% of Earth's mass. Since gravitational force is directly proportional to mass, Pluto's tiny mass results in a very weak gravitational field. On Pluto, a person weighing 70 kg (686 N) on Earth would weigh only about 4.2 kg (41 N). This extremely low gravity is one of many factors that led to Pluto's reclassification from a planet to a dwarf planet in 2006.
Extended exposure to zero or low gravity environments causes significant health effects in humans. Without the constant pull of Earth's gravity, astronauts experience: (1) Bone density loss at a rate of 1-2% per month, (2) Muscle atrophy, particularly in the legs and lower back, (3) Cardiovascular changes including fluid shifts toward the head and reduced heart efficiency, (4) Vision impairment due to pressure changes in cerebrospinal fluid, and (5) Balance and coordination problems upon return to Earth. These effects are why astronauts on the International Space Station follow rigorous exercise regimens and why understanding the gravity of potential destination planets is needed for planning long-term space missions or colonization.