ForHosting KIT · Developer Utilities

Weight at latitude calculator

A bathroom scale does not report your mass. It reports the contact force that balances your apparent weight, and that force changes with geographic latitude because Earth is spinning.

● BetaFree · in your browser

Run — free How it works & API

Use it from WebAPIEmailTelegramApp soon

This weight at latitude calculator takes a mass in kilograms and a latitude in degrees and returns the measured weight in newtons after subtracting the local-vertical component of centrifugal acceleration from standard gravity. The model is the first-order rotating-sphere correction used in introductory geophysics and mechanics: effective g equals g-zero minus omega-squared times R times cosine-squared of latitude. Poles keep the full reference g; the equator is lighter by about 0.034 metres per second squared. Latitude outside minus ninety to ninety is rejected as invalid input. The same deterministic arithmetic powers the free browser widget and the API, with no network, no sampling, and no clock. Use it to compare a seventy-kilogram person at Quito and at Helsinki, to seed lab fixtures, or to show why a spring scale and a mass balance disagree when you travel.

How to use it

Enter your values in the form above. The tool checks them before calculating and shows the result on the same page.

Check your inputs

Use the labels and units shown next to each field. If something is missing or outside the allowed range, the page points to the field to fix.

Use it again or automate it

Use the browser tool for individual checks and the API when you need the same capability in an automated workflow.

What you can do with it

Get an answer now

Enter one set of values and see the result without building a spreadsheet or script.

Compare scenarios

Change one value at a time and rerun the calculation to understand what affects the result.

Automate repeated work

Use the API when the same calculation needs to run inside your product or workflow.

FAQ

How do I use this capability?

Complete the fields above and run it on this page. The form highlights anything that needs attention.

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

POSThttps://api.kit.forhosting.com/mech/weight-at-latitude

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/mech/weight-at-latitude \
  -H "Authorization: Bearer $KIT_KEY" \
  -H "Content-Type: application/json" \
  -d '{"mass":70,"latitude":45}'

const res = await fetch("https://api.kit.forhosting.com/mech/weight-at-latitude", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.KIT_KEY}`,
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "mass": 70,
    "latitude": 45
  })
});
const { task_id } = await res.json();

import os, requests

res = requests.post(
    "https://api.kit.forhosting.com/mech/weight-at-latitude",
    headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
    json={
    "mass": 70,
    "latitude": 45
},
)
task_id = res.json()["task_id"]

<?php
$res = file_get_contents("https://api.kit.forhosting.com/mech/weight-at-latitude", false, stream_context_create([
  "http" => [
    "method"  => "POST",
    "header"  => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
    "content" => '{"mass":70,"latitude":45}',
  ],
]));
$task = json_decode($res, true);

body := bytes.NewBufferString(`{"mass":70,"latitude":45}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/mech/weight-at-latitude", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)

Example request

{
  "mass": 70,
  "latitude": 45
}

Example response

{
  "task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
  "type": "mech.weight_at_latitude",
  "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

Per request$0.002

Published price — no tokens, no invented credits. A failed task is never charged.

Limits

`max_abs_mass`	1000000000000000
`min_latitude`	-90
`max_latitude`	90

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.

Read the full KIT documentation →