Gas pressure from moles calculator
Find the pressure inside a sealed vessel: 1 mol of gas in 0.024465 m³ at 298.15 K presses at about one atmosphere, or 101326.6719622604 Pa. Enter a matching gas constant to work in litres and atmospheres. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Moles
- 1
- Volume
- 0.024465
- Creativity
- 298.15
- Resistance (Ω)
- 8.314462618
- Pressure
- 101,326.6719622604
Ideal-gas pressure follows directly from the equation of state once the amount of substance, the container volume, and the absolute temperature are known. Rearranging PV equals nRT into pressure yields P equals n R T over V, the standard classroom and laboratory shortcut for sealed vessels, homework checks, and light process estimates under the ideal-gas assumption.
Ideal-gas pressure formula and how to choose inputs
Start from the ideal-gas law P V equals n R T. Solving for pressure produces the working identity P equals n times R times T divided by V. Moles and absolute temperature must also be positive so the returned pressure is a meaningful positive scalar under the ideal-gas model.
If you work in litres and atmospheres, pass a matching R such as zero point zero eight two zero five seven and keep every field coherent—the engine does not convert units automatically. Classroom problems that state volume in litres and expect atmospheres should therefore set r consistently rather than mixing SI defaults with non-SI volumes.
What you can do with it
Homework and exam verification
Students compute ideal-gas pressure from n, V, and T, compare against worked solutions near room conditions, and get a clear error when zero or negative volume is submitted by mistake.
Lab notebooks and vessel estimates
Digital notebooks and pilot-plant helpers estimate sealed-vessel pressure under the ideal-gas assumption for air, nitrogen, or other light gases without embedding a thermo database.
FAQ
What happens if volume is zero or negative?
Volume must be strictly positive; zero or negative volume is rejected and not charged.
What units does the calculator use?
For L·atm or other systems, pass a matching gas constant r and keep all fields coherent.
Is the gas pressure from moles calculator free?
The browser tool runs free on your device.
Does this support real gases?
No. This capability implements the ideal-gas law only. Near condensation or at high pressure you need a real-gas equation of state, which is out of scope here.
Why is my pressure a thousand times too high?
With the default gas constant the volume must be in cubic metres. Entering litres without changing R makes the result a thousand times too large; convert the volume, or use a litre-atmosphere constant such as 0.082057. Also check that the temperature is in kelvin.
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/chem/gas-pressure-from-moles \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"moles":1,"volume":0.024465,"temperature":298.15}'const res = await fetch("https://api.kit.forhosting.com/chem/gas-pressure-from-moles", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"moles": 1,
"volume": 0.024465,
"temperature": 298.15
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/chem/gas-pressure-from-moles",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"moles": 1,
"volume": 0.024465,
"temperature": 298.15
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/chem/gas-pressure-from-moles", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"moles":1,"volume":0.024465,"temperature":298.15}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"moles":1,"volume":0.024465,"temperature":298.15}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/chem/gas-pressure-from-moles", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"moles": 1,
"volume": 0.024465,
"temperature": 298.15
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "chem.gas_pressure_from_moles",
"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 capability evaluates that formula deterministically with a CODATA default gas constant, accepts a custom R when your unit system is not SI, rejects zero or negative volume with a clear invalid input error, and returns JSON that lab notebooks, tutoring apps, and lightweight chemistry services can pin in tests without a thermo package.
Ideal-gas pressure formula and how to choose inputs
Send required fields moles, volume, and temperature as finite JSON numbers or numeric strings; aliases n, amount, mol for moles, V, v, vol for volume, and T, t, temp for temperature are accepted. Volume must be strictly positive: zero or negative values are invalid_input because the denominator would be singular or non-physical. Optional field r (aliases gas_constant, R) defaults to eight point three one four four six two six one eight joules per mole kelvin, the CODATA molar gas constant; with volume in cubic metres and temperature in kelvin the pressure unit is pascals. Identical inputs always produce identical JSON because the path is pure arithmetic with no network, no random seed, and no wall clock.
Reading the pressure response and validating physical sense
Use pressure alone when a dashboard only needs the scalar; use the echoed inputs when grading software must confirm that unit choices and R were not silently changed; use formula and method when audit logs need a human-readable identity. Typical one-mole air checks near twenty-four point five litres at room temperature land near one atmosphere when a litre-atmosphere gas constant is used—if your SI result is orders of magnitude off, verify that volume is in cubic metres rather than litres without adjusting R, or that temperature is absolute kelvin rather than Celsius. The formula label is always the string P equals n R T over V, and method is always ideal_gas_pressure so downstream code can branch without sniffing shapes. Missing required fields, non-finite numbers, non-positive moles or temperature, custom R that is not positive, and volume less than or equal to zero all fail with invalid_input and are not charged. Magnitude caps reject absurd scientific-notation extremes that would overflow a Worker isolate while still covering every classroom and pilot-scale vessel example.
API usage, pricing, lab workflows, and practical limits
Call the free in-browser gas pressure from moles calculator for homework checks, lecture demos, and quick sanity tests on sealed flasks or lecture demos without installing a full process simulator. The ideal-gas model breaks down near condensation, at very high pressure, or for strongly non-ideal mixtures—those cases need a real-gas equation of state and are out of scope here by design. Authors shipping SDKs can map the pressure field straight into UI readouts while showing formula as a caption so students see the same P equals n R T over V identity they write by hand on worksheets. Send a JSON body with moles, volume, and temperature, and optionally r when you are not using SI. Use the prepaid API when a tutoring platform, digital lab notebook, SCADA helper, or curriculum generator needs a stable contract under KIT balance at $0.002 per successful item; validation failures never consume balance after the engine rejects the request. Pair this endpoint with ideal-gas density tools when you already know pressure and need mass density, or with Dalton mole-fraction helpers when the next step is partial pressures from composition.
Integration use cases
Tutoring and curriculum generators
Lesson builders produce stable JSON for pressure drills, flashcards, and auto-graded gas-law problems at $0.002 per successful API item.
Technical questions
How do I calculate gas pressure from moles?
Send JSON with moles (n), volume (V), and temperature (T in kelvin). The response returns pressure from the ideal-gas law P=nRT/V using the CODATA default R unless you pass a custom r.