Weight on other planets calculator
Find your weight on another world from your bathroom-scale reading: 70 kg on Earth becomes 26.39 on Mars, where gravity is 0.377 of Earth's, in the same unit you typed. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Weight
- 70
- Target body name
- mars
- Planet name
- Mars
- Gravity ratio
- 0.377
- G ms2
- 3.71
- Weight on planet
- 26.39
How much would you weigh on Mars, on the Moon, or on Jupiter? Weight is the force of gravity on a mass, so the number on a bathroom scale changes when surface gravity changes even though your mass stays the same. Ratios cover Mercury, Venus, Earth, the Moon, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto, and the Sun using stable educational table values, so classroom demos and popular-science pages never drift. Enter any non-negative Earth weight in kilograms, pounds, or another unit you prefer; the result uses the same unit because the conversion factor is dimensionless. Unknown planet names fail with a clear validation error instead of silently falling back to Earth.
How planetary weight conversion works
On Earth your scale reading is the contact force that balances local weight, roughly mass times g_Earth where g_Earth is about 9.81 metres per second squared near the surface. Multiplying your Earth weight by the table entry for the chosen body yields the equivalent weight in the same unit you typed. The response also reports the absolute surface gravity in metres per second squared so physics teachers can connect the dimensionless ratio to SI units without a second lookup.
Weight must be finite and non-negative; NaN, Infinity, and negative values are rejected.
What you send and what you get back
Send two fields: weight, a finite non-negative number for your Earth scale reading in any unit you choose, and planet, a string naming the target body. Both fields are required. Classic checks include seventy kilograms on Mars giving about 26.4 kilograms-weight at ratio 0.377, the same mass on the Moon near 11.6, and on Jupiter above 165.
Earth as the target simply returns the input weight with ratio 1. Because the unit of weight is never converted internally, a caller who sends pounds receives pounds-force equivalent on the target body, which keeps the UX simple for mixed metric and imperial audiences.
Where weight-on-planet calculators show up in real work
Middle-school and high-school science units introduce weight versus mass with Moon and Mars comparisons; a single trusted oracle that returns both the ratio and absolute g speeds demos and auto-graded quizzes. Planetarium and museum kiosks print visitor weight cards for each body in the Solar System walk, and they need deterministic table values that do not change between firmware updates. Game designers balancing lunar bases, Mars rovers, or low-gravity platformers often start from Earth character stats scaled by surface gravity ratios before they add local terrain modifiers.
Content sites ranking for weight on other planets calculator need a clean landing with honest limits: this tool is mean surface gravity, not free-fall in orbit, not altitude above Olympus Mons, and not centrifugal reduction at the equator. If you later need Newton's two-body force F equals G m1 m2 over r squared, orbital period from Kepler's third law, or unit conversion between kilograms and pounds without a gravity story, treat those as separate search intents and landings rather than overloading this planetary weight page.
What you can do with it
Classroom weight versus mass demos
Show students that 70 kg on Earth becomes about 26 kg-weight on Mars and 11 kg-weight on the Moon using one stable gravity table.
Game and simulation gravity presets
Bootstrap character mass-to-weight scaling for lunar, Martian, or Jovian levels from documented surface-gravity ratios.
FAQ
How is weight on another planet calculated?
The capability multiplies your Earth weight by a fixed surface-gravity ratio for the chosen body.
Which planets and bodies are supported?
Mercury, Venus, Earth, Moon, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto, and the Sun.
Do I need to pick kilograms or pounds?
No. The ratio is dimensionless, so any unit you enter for Earth weight is used unchanged for the result. Seventy kilograms stays kilograms; one hundred fifty pounds stays pounds.
What does it cost?
The browser tool is free and runs locally.
Does my mass change on another planet?
No. Your mass stays the same everywhere; only weight, the pull of gravity on that mass, changes with surface gravity. That is why 70 kilograms on Earth reads 26.39 on Mars even though nothing about your body has changed.
Related tools
For developers — API access
Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.
API endpoint
Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.
Call it from your stack
curl -X POST https://api.kit.forhosting.com/astro/weight-on-planet \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"weight":70,"planet":"mars"}'const res = await fetch("https://api.kit.forhosting.com/astro/weight-on-planet", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"weight": 70,
"planet": "mars"
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/astro/weight-on-planet",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"weight": 70,
"planet": "mars"
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/astro/weight-on-planet", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"weight":70,"planet":"mars"}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"weight":70,"planet":"mars"}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/astro/weight-on-planet", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"weight": 70,
"planet": "mars"
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "astro.weight_on_planet",
"status": "queued",
"_links": {
"result": "/tasks/tsk_…/result"
}
}The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.
Pricing
Published price — no tokens, no invented credits. A failed task is never charged.
Errors
| HTTP | Code | Meaning |
|---|---|---|
401 | unauthorized | Missing or invalid API key. |
402 | insufficient_balance | Your balance doesn't cover the task price. |
404 | unknown_type | That task type doesn't exist. |
429 | rate_limited | Too many requests. Use the webhook instead of polling. |
Technical notes
This calculator multiplies your Earth weight by the mean surface-gravity ratio of a chosen Solar System body: weight on planet equals weight on Earth times g_planet over g_Earth.
How planetary weight conversion works
On another body the same mass feels a different surface acceleration g_planet, so the scale reading scales by the ratio g_planet divided by g_Earth. This capability stores a fixed table of those ratios for the major Solar System bodies people usually ask about: Mercury near 0.38, Venus near 0.91, Earth exactly 1, the Moon near 0.17, Mars near 0.38, Jupiter above 2.3, Saturn near 0.92, Uranus near 0.89, Neptune near 1.12, Pluto near 0.07, and the Sun near 28. The pipeline is pure arithmetic: no network calls, no random seeds, no wall-clock timestamps, and no model drift, so identical inputs always produce identical JSON. Planet names are matched case-insensitively after trim, with a few aliases such as luna for the Moon, and any unknown name raises invalid_input listing the supported set.
What you send and what you get back
Missing fields, non-numeric weight, NaN, Infinity, negative weight, and unknown planet names fail with invalid_input and are not charged. On success the response echoes the cleaned Earth weight, the normalized planet key in lowercase, a display planet_name such as Mars, the gravity_ratio used, g_ms2 as absolute surface gravity, weight_on_planet as the scaled result, plus formula and method strings for audit trails. Pricing for successful API calls is the published base of $0.002 per item; validation failures do not consume prepaid balance.
Where weight-on-planet calculators show up in real work
Because this capability is a pure parse engine, API pricing is the published base of $0.002 per successful item and failed validation does not consume balance.
Integration use cases
Museum and planetarium visitor cards
Print each guest's equivalent weight on every planet from a single API call so kiosks and staff tablets never disagree.
Technical questions
What happens if the planet name is wrong?
The request fails with invalid_input and a message listing supported bodies. Typos are not silently mapped to Earth.