At a glance
- On the Moon, gravity is about a sixth of Earth's, so scales would read about 0.17 times your Earth weight.
- Jupiter pulls hardest: about 2.53 times Earth's gravity, measured at the cloud tops.
- A year lasts 88 Earth days on Mercury but 165 Earth years on Neptune.
- Your mass stays the same everywhere; only the pull of gravity changes.
- Nothing you enter is stored or sent anywhere.
Interactive tool
Your weight and age on other planets
Enter your weight and date of birth. Everything is worked out in your browser: nothing is stored or sent anywhere.
| World | Gravity (Earth = 1) | Your weight there | Your age there |
|---|---|---|---|
| Mercury | 0.378 | 26.5 kg | Add your date of birth |
| Venus | 0.904 | 63.3 kg | Add your date of birth |
| Earth | 1 | 70 kg | Add your date of birth |
| The Moontravels round the Sun with Earth | 0.165 | 11.6 kg | Add your date of birth |
| Mars | 0.377 | 26.4 kg | Add your date of birth |
| Jupiterat the cloud tops | 2.528 | 177 kg | Add your date of birth |
| Saturnat the cloud tops | 1.065 | 74.6 kg | Add your date of birth |
| Uranusat the cloud tops | 0.886 | 62 kg | Add your date of birth |
| Neptuneat the cloud tops | 1.137 | 79.6 kg | Add your date of birth |
| Plutoa dwarf planet | 0.063 | 4.4 kg | Add your date of birth |
Your mass stays the same everywhere; what changes is how hard each world pulls on it, which is what bathroom scales measure. Gravity figures are rounded averages at the surface, or at the cloud tops for the giant planets, which have no solid ground.
How to use this tool
- Enter your weight and choose kilograms, pounds or stone.
- Add your date of birth.
- Read the table to see your weight and your age on Mercury, Venus, the Moon, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto.
- Change the numbers as often as you like: nothing is saved or sent anywhere.
Weight and mass are not the same
In everyday speech, weight and mass mean the same thing, but scientists separate them. Mass is the amount of matter in you, and it stays the same whether you are at home, on the Moon or floating in orbit. Weight is the pull of gravity on that mass, so it changes from world to world.
Bathroom scales actually measure that pull and then display it as kilograms, pounds or stone. The tool does the same: it shows what a set of scales would read if you stood on each world. Your body would not change at all, only the strength of the pull holding you down.
Crews on the International Space Station float not because there is no gravity up there, but because they are falling around Earth together with the station. The orbit calculator shows how fast that endless fall is.
Why your weight on other planets changes
The pull of gravity at a world's surface depends on two things: how much mass the world has, and how far its surface is from its centre. More mass means a stronger pull. A bigger size puts you farther from the centre, which weakens it.
That balance produces some surprises. Mars and Mercury are very different worlds, yet both pull at about 0.38 times Earth's gravity. Saturn has far more mass than Earth, but it is so large that its pull at the cloud tops is only about 1.07 times Earth's. Uranus, at 0.89, is gentler than Earth, while Jupiter, at 2.53, is the heavyweight of the table.
The giant planets have no solid ground to stand on, so the tool measures their gravity at the cloud tops. Pluto, now classed as a dwarf planet, pulls at just 0.06 times Earth's gravity.
Why your age on other planets depends on the length of a year
A year is the time a world takes to travel once around the Sun. Planets close to the Sun move faster along shorter paths, so their years are short. Planets far away move more slowly along much bigger paths, so their years are very long.
Mercury, the closest planet, races round in 88 Earth days. Venus takes 225 days and Mars 687 days, or 1.88 Earth years. Out among the giants, a year lasts 11.9 Earth years on Jupiter, 29.5 on Saturn, 84 on Uranus and 165 on Neptune. The tool divides the time since you were born by each world's year to find your age there.
The Moon is a special case. It travels around the Sun together with Earth, so it shares Earth's year and your age there matches your age at home.
Fun comparisons to try
Once you have your own results, try these comparisons with friends or family.
- Jumping on the Moon: with about a sixth of Earth's gravity, the same leap would carry you about six times higher, which is why moonwalkers bounded rather than walked.
- A young age on Neptune: one Neptune year lasts 165 Earth years, so nobody alive today has reached their first Neptune birthday.
- Birthdays on Mercury: a ten-year-old on Earth has already circled the Sun more than 40 times in Mercury years.
- Heavy going on Jupiter: a backpack that feels easy on Earth would feel about two and a half times heavier at Jupiter's cloud tops.
- Featherweight on Pluto: at 0.06 times Earth's gravity, a person who weighs 50 kg at home would register just 3 kg on the scales.
A note for teachers and families
This tool works well in the classroom or at the kitchen table. Pupils can predict which world makes them heaviest before checking, convert between kilograms, pounds and stone, or compare age against distance from the Sun to spot the pattern for themselves.
Privacy is built in. Weight and date of birth are personal details, so nothing entered here is stored or sent anywhere: everything stays on the device in front of you. Children can use made-up numbers too, which works just as well for learning.
For a wider introduction, the beginner's guide to learning about space tours the Solar System, and the Moon, Mars and beyond looks at where exploration may head next.
Nicole Junkermann's perspective on curiosity and learning
Nicole Junkermann has long been interested in how people learn and how curiosity opens doors to new careers. She often describes the real story of technology and work as reinvention rather than replacement, and reinvention usually starts with a simple question, such as why a person would weigh less on Mars.
In her view, small playful tools like this one are a good way in. They turn big ideas such as gravity and orbits into something personal, and that personal spark is often what draws someone towards science, engineering or AI. The blog post on reinvention and working lives in AI and space explores where that curiosity can lead.
To keep exploring, find out how long a message takes to reach each of these worlds with the space signal delay calculator.
Frequently asked questions
How much would you weigh on Mars?
Mars has about 0.38 times Earth's surface gravity, so you would weigh a little under two fifths of your Earth weight. Someone who weighs 70 kg on Earth would see about 27 kg on the scales on Mars. Your mass, the amount of matter in your body, would not change at all.
How old would you be on other planets?
Your age on another planet depends on how long that planet takes to travel around the Sun. A year on Mars lasts 687 Earth days, so you would be roughly half your Earth age there, while on Mercury you would be more than four times older. On Neptune, with a year of 165 Earth years, nobody alive today has yet had a first birthday.
Which planet has the strongest gravity?
Jupiter has the strongest gravity of the planets, about 2.53 times Earth's at the cloud tops, so you would weigh roughly two and a half times as much there. Jupiter has no solid surface, so the figure is measured at the level of its clouds.
Why is Pluto included if it is not a planet?
Pluto is classed as a dwarf planet, but it remains a favourite world to compare. Its gravity is only about 0.06 times Earth's, so it shows how small a pull can be. The space glossary explains dwarf planets and many other terms.
Does the weight and age tool store your details?
No. Nothing entered into the weight and age tool is stored or sent anywhere, and everything stays on the device in front of you. That makes it suitable for classrooms and families.
How does Nicole Junkermann think about learning about space?
Nicole Junkermann sees curiosity as the starting point for learning and for new careers in science and technology. Simple, personal tools like this one make big ideas about gravity and orbits easy to explore, which fits her wider interest in learning and reinvention.