ForHosting KIT · Developer Utilities

Number of atoms in sample calculator

Counting every atom in a weighed sample is a standard bridge between bulk laboratory mass and the microscopic world of Avogadro-scale numbers.

● BetaFree · in your browser

Run — free How it works & API

Use it from WebAPIEmailTelegramApp soon

Given the mass of a pure substance, its molar mass, and how many atoms sit in one formula unit, the total atom count is the product of moles, Avogadro’s constant, and that per-unit atom count: N equals (m over M) times N_A times n_atoms. Students meet the chain when a worksheet asks how many atoms are in eighteen grams of water or twenty-four grams of carbon; analysts use it when translating a solid weigh-out into particle counts for surface-coverage or defect models; curriculum authors need a single deterministic oracle that never drifts between the free browser form and the paid API. This calculator accepts mass in grams, molar mass in grams per mole, and a positive atoms-per-formula-unit count, returns moles, formula-unit count, and total atoms with unit labels and the formula string for audit, and rejects zero or negative molar mass so a division by zero never becomes Infinity or a silent NaN. No network, no random seeds, and no wall-clock timestamps: identical inputs always produce identical JSON.

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/chem/number-of-atoms-in-sample

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/chem/number-of-atoms-in-sample \
  -H "Authorization: Bearer $KIT_KEY" \
  -H "Content-Type: application/json" \
  -d '{"mass_g":18.015,"molar_mass":18.015,"atoms_per_formula_unit":3}'

const res = await fetch("https://api.kit.forhosting.com/chem/number-of-atoms-in-sample", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.KIT_KEY}`,
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "mass_g": 18.015,
    "molar_mass": 18.015,
    "atoms_per_formula_unit": 3
  })
});
const { task_id } = await res.json();

import os, requests

res = requests.post(
    "https://api.kit.forhosting.com/chem/number-of-atoms-in-sample",
    headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
    json={
    "mass_g": 18.015,
    "molar_mass": 18.015,
    "atoms_per_formula_unit": 3
},
)
task_id = res.json()["task_id"]

<?php
$res = file_get_contents("https://api.kit.forhosting.com/chem/number-of-atoms-in-sample", false, stream_context_create([
  "http" => [
    "method"  => "POST",
    "header"  => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
    "content" => '{"mass_g":18.015,"molar_mass":18.015,"atoms_per_formula_unit":3}',
  ],
]));
$task = json_decode($res, true);

body := bytes.NewBufferString(`{"mass_g":18.015,"molar_mass":18.015,"atoms_per_formula_unit":3}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/chem/number-of-atoms-in-sample", 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_g": 18.015,
  "molar_mass": 18.015,
  "atoms_per_formula_unit": 3
}

Example response

{
  "task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
  "type": "chem.number_of_atoms_in_sample",
  "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.

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 →

Run — free