🪐Weight on Other Planets Calculator
Enter your weight once and explore two planetary systems — switch between kilograms, pounds, and stone, and see your weight on every body instantly.
Free Weight on Other Planets Calculator Online
Ever wondered how much you'd weigh on Mars, the Moon — or a planet orbiting another star? Our free Weight on Other Planets calculator shows you instantly. Enter your weight once and explore two named planetary systems: Our Solar System, with all eight planets plus the Moon, the Sun, and Pluto, and the real TRAPPIST-1 System, a family of seven rocky worlds about 39 light-years away.
Switch between systems with a tap, change between kilograms, pounds, and stone, and compare each world's gravity against Earth's. Because gravity differs on every world, the same you could feel feather-light on one and crushingly heavy on another. TRAPPIST-1's planets are included because they're unusually well-measured — so the weights you see there are based on real science, not guesswork.
Simply enter your weight and explore. No sign-up, no downloads, no limits — just fun, accurate results whenever you need them.
About the Weight on Other Planets Calculator
Key features
Two named planetary systems
Switch between Our Solar System (11 bodies) and the real TRAPPIST-1 System (7 exoplanets) with a single tap. Weight and unit are preserved across both systems.
Real exoplanet gravity data
TRAPPIST-1 planets are included because both their mass and radius have been precisely measured — so the weights shown are based on real science, not approximations.
kg, lb, and stone switching
Switch freely between kilograms, pounds, and stone. Your input auto-converts when you change units so you never need to re-type your weight — works across both systems.
Gravity comparison per body
Each card shows the gravity multiplier and a proportional bar so you can instantly compare gravitational strength — within and between planetary systems.
Mass versus weight
Your mass — the amount of matter that makes you up — is constant everywhere in the universe. Weight is the force of gravity on that mass, measured in newtons (or colloquially in kg/lb/st). Because gravitational pull varies from world to world, your weight changes while your mass does not. On the Moon you'd weigh about one-sixth of your Earth weight; on Jupiter you'd weigh more than twice as much.
The TRAPPIST-1 System
TRAPPIST-1 is an ultracool M-dwarf star about one-tenth the mass and size of our Sun, located ~39 light-years away in Aquarius. It hosts seven known rocky planets, all in or near its habitable zone. What makes this system special for this tool is that the TRAPPIST-1 planets are among the most precisely characterised exoplanets known — both mass (from transit timing variations) and radius (from transit photometry) have been measured for all seven, allowing surface gravity to be reliably computed.
TRAPPIST-1 e has gravity closest to Earth's (~0.91×) — the most Earth-like world in the system by this measure. TRAPPIST-1 d has the lowest gravity (~0.48×). In reality, several of these planets may be tidally locked, frozen, or have thick atmospheres — the weights shown are a hypothetical comparison of gravitational pull, not an assessment of habitability.
Who it's for
Students
Understand the difference between mass and weight hands-on, explore real exoplanet data, or verify homework answers about planetary gravity.
Teachers
Project the calculator on screen to make gravity tangible — enter a student's weight and let them see how it would change on Mars, Jupiter, or a real exoplanet.
Space enthusiasts
Explore what daily life might feel like under different gravitational conditions, from Pluto's feather-light pull to the crushing weight of the Sun.
Curious kids
A fun, no-jargon way to explore the solar system and beyond — enter your weight and discover where in the universe you'd feel the lightest.
Gravity ratios used
Each result is your Earth weight multiplied by the body's surface-gravity ratio relative to Earth's 9.807 m/s². For gas giants, "surface" gravity is measured at the cloud-top level; for the Sun, it is at the photosphere.
Our Solar System
| Body | Gravity ratio | Type |
|---|---|---|
| Mercury | ×0.378 | Rocky planet |
| Venus | ×0.907 | Rocky planet |
| Earth | ×1.000 | Reference |
| Moon | ×0.165 | Natural satellite |
| Mars | ×0.377 | Rocky planet |
| Jupiter | ×2.360 | Gas giant (cloud top) |
| Saturn | ×0.916 | Gas giant (cloud top) |
| Uranus | ×0.889 | Ice giant (cloud top) |
| Neptune | ×1.120 | Ice giant (cloud top) |
| Pluto | ×0.063 | Dwarf planet |
| Sun | ×27.900 | Star (photosphere) |
TRAPPIST-1 System
| Body | Gravity ratio | Note |
|---|---|---|
| TRAPPIST-1 b | ×0.817 | Rocky exoplanet |
| TRAPPIST-1 c | ×0.961 | Rocky exoplanet |
| TRAPPIST-1 d | ×0.478 | Lowest gravity in system |
| TRAPPIST-1 e | ×0.912 | Most Earth-like gravity |
| TRAPPIST-1 f | ×0.855 | Rocky exoplanet |
| TRAPPIST-1 g | ×0.901 | Rocky exoplanet |
| TRAPPIST-1 h | ×0.581 | Rocky exoplanet |
TRAPPIST-1 gravity ratios are computed from measured mass and radius values in: Agol, E. et al. (2021) "Refining the Transit-timing and Photometric-dynamical Model of the TRAPPIST-1 Planetary System", PSJ 2:1, doi:10.3847/PSJ/abd022. These are best estimates — exoplanet measurements carry inherent uncertainty and values may be refined as new data becomes available.
How the calculation works
The tool converts your input to kilograms, multiplies by each body's gravity ratio, then converts back to your chosen unit. The formula is: weight_on_body = weight_earth_kg × gravity_ratio, then converted to lb or stone if needed.
Unit conversions use exact factors: 1 kg = 2.20462 lb and 1 stone = 6.35029 kg. Switching units auto-converts your input through the same chain so round-trip accuracy is preserved. Both planetary systems share the same input and unit state — switching systems never changes your entered weight or unit.
Frequently Asked Questions
How does the weight on other planets calculator work?
Enter your weight on Earth and the tool multiplies it by each body's surface-gravity ratio, showing what you'd weigh across the chosen planetary system — no button refresh needed. Switch between Our Solar System and the TRAPPIST-1 System using the tabs above the results; your entered weight and chosen unit are preserved when you switch.
Is this calculator free to use?
Yes, it's completely free with no sign-up, downloads, or limits. Calculate as many weights as you like, as often as you like.
Can I see my weight on planets outside the solar system?
Yes. Switch to the TRAPPIST-1 System tab to see your weight on seven real exoplanets orbiting another star about 39 light-years from Earth, in the constellation Aquarius. TRAPPIST-1 is an ultracool dwarf star — much smaller and cooler than our Sun — and its planets are the most precisely measured exoplanets known.
How do you know the gravity on an exoplanet?
Surface gravity depends on a planet's mass and radius (g ∝ M/R²). The TRAPPIST-1 planets are included precisely because both have been measured well — mass via transit timing variations, and radius via transit photometry. Only bodies with both measurements are listed. Worlds known only by minimum mass or only by radius are excluded because gravity can't be reliably computed without both. The values shown are best estimates from current measurements and carry inherent uncertainty, as noted in the tool.
Why does my weight change between worlds but my mass doesn't?
Your mass — the amount of matter in you — stays constant everywhere in the universe. Weight is the force that gravity exerts on that mass, so it varies depending on each world's gravitational pull. On the Moon, gravity is only about 16.5% of Earth's, so you'd feel much lighter even though you're exactly the same person carrying exactly the same matter.
Which bodies are included?
In Our Solar System: all eight planets (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune) plus the Moon, the Sun, and Pluto — eleven bodies in total. Earth is shown as your reference point so you can confirm your input before comparing. In the TRAPPIST-1 System: planets b, c, d, e, f, g, and h.
Can I switch between kg, pounds, and stone?
Yes. Enter and view your weight in kilograms, pounds, or stone, and every result updates instantly in your chosen unit. Switching units also auto-converts your input value — so you never have to re-type your weight. The same conversion applies when viewing either planetary system.
Where would I weigh the most and the least?
In the Solar System you'd weigh most on the Sun (about 27.9× your Earth weight), then Jupiter at about 2.36×. You'd weigh least on Pluto (just 6.3% of Earth weight) and the Moon (16.5%). In the TRAPPIST-1 System, TRAPPIST-1 e has gravity closest to Earth's (~0.91×), making it the most Earth-like, while TRAPPIST-1 d is the lightest at ~0.48×.
Is my data stored anywhere?
No. Your weight is processed directly in your browser and is never stored or sent to a server, keeping your information completely private. Close the tab and everything is gone.
Could I actually stand on these worlds?
Not really. Gas giants and the Sun have no solid surface, and several TRAPPIST-1 planets may be tidally locked, frozen, or wrapped in thick atmospheres — none are places a person could comfortably stand. The figures are a fun, hypothetical comparison of gravitational pull, not a survivable scenario. Think of it as a thought experiment in physics.