mmHg to atm converter
Divide a mercury-column reading by exactly 760 to get standard atmospheres: 760 mmHg is 1 atm and 1 mmHg is 0.001315789474 atm. Made for gas-law homework, barometer readings and vacuum sheets. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Mmhg
- 760
- Result
- 1 atm
- Converted
- 1
- Atm
- 1
- From unit
- mmHg
A millimeters-of-mercury to atmospheres converter turns a mercury-column pressure reading into the standard-atmosphere value used in gas-law homework, weather reference tables, vacuum process sheets, and many chemistry lab reports.
Why mmHg and atmospheres still meet at an exact factor
Millimeters of mercury remain the everyday column-height unit on many blood-pressure contexts, barometric teaching demos, manometer lab sheets, and vacuum roughing charts that still quote torr or mmHg side by side. Standard atmospheres belong to the gas-law and STP family used in chemistry textbooks, ideal-gas homework, and weather reference tables that fix one atmosphere as the baseline pressure scale.
The bridge between them is not a memorised survey rule of thumb: by the conventional standard-atmosphere definition used across engineering and chemistry tables, one atmosphere equals exactly seven hundred sixty millimeters of mercury. That makes the conversion a single exact division, atmospheres equals millimeters of mercury divided by seven hundred sixty. Teachers sometimes still teach divide by about seven hundred sixty with intermediate rounding, but truncating too early drifts on multi-atmosphere compressor stages or high-vacuum gauge chains expressed in mmHg.
Practically, seven hundred sixty mmHg is the one-atmosphere identity check every student learns first, and this tool preserves that identity after fixed twelve-decimal rounding.
Practical tips, checks, and related searches
Round-trip sanity checks are easy: convert seven hundred sixty mmHg and confirm you receive exactly one atmosphere after rounding, or convert one hundred fifty two mmHg and confirm the result is one fifth of an atmosphere within the same twelve-decimal policy. When teaching, pair the exact path with the mental shortcut of seven hundred sixty so students see that the identity case is preserved without intermediate truncation. Stay inside the absolute range so the divide cannot overflow into a non-finite result the solver must reject.
This landing targets people searching for mmHg to atm, convert millimeters of mercury to atmospheres, or an exact mmHg pressure calculator; it is not a general multi-unit pressure hub, not an atm-to-mmHg primary form, not a vacuum micron converter, and not a blood-pressure category tool. Prefer this capability when the input is already in mmHg and you only need atmospheres; if you must convert among many pressure units in one call, use a broader pressure converter instead.
Document the factor one atmosphere equals seven hundred sixty mmHg in lab notebooks so graders can reproduce the same arithmetic without depending on a rounded table snippet from an older textbook appendix.
What you can do with it
Chemistry lab and gas-law homework
Turn manometer or barometer readings in mmHg into atmospheres for ideal-gas and STP calculations with the same exact factor every row.
Process and vacuum sheet bridging
Map mmHg-scale roughing or manometer setpoints into atmosphere fields on European or textbook process sheets without survey rounding.
Teaching and worksheet checks
Students convert classroom mmHg readings to atm and compare hand work against deterministic steps before submitting lab reports.
FAQ
What factor converts mmHg to atm?
By the conventional standard-atmosphere definition, one atmosphere equals exactly 760 millimeters of mercury.
What input field do I send?
Send a finite number in the field mmhg.
Is the mmHg to atm converter free?
The browser tool is free and runs locally.
How much is 1 mmHg in atmospheres?
One millimetre of mercury is 0.001315789474 atm, which is 1 divided by 760 rounded to twelve decimals. Multiply any reading by that factor, or more simply divide it by 760.
Why not round the factor halfway through?
Because truncating early makes results drift on multi-atmosphere compressor stages or long high-vacuum gauge chains. The converter divides by 760 exactly and rounds only at the end, so 760 mmHg always returns exactly 1 atm.
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/conv/mmhg-to-atm \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"mmhg":760}'const res = await fetch("https://api.kit.forhosting.com/conv/mmhg-to-atm", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"mmhg": 760
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/conv/mmhg-to-atm",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"mmhg": 760
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/conv/mmhg-to-atm", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"mmhg":760}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"mmhg":760}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/conv/mmhg-to-atm", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"mmhg": 760
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "conv.mmhg_to_atm",
"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
Invalid or missing input fails with a clear invalid_input error instead of inventing a number.
How to call the API and what comes back
Absolute values must stay within the published limit of one trillion. Prefer bare numbers when you control the client; string numbers are accepted only when they match a strict finite numeric pattern without units, thousand separators, or currency symbols embedded in the field. Send a JSON body with one required finite number field named mmhg. Aliases mmHg, mm_hg, torr, value, pressure, and mmhg_value are accepted so SDK clients and form posts can use the name that fits the product. On success the response echoes rounded mmhg, sets atm, result, and converted to the same rounded atmosphere magnitude, unit to the token atm, from_unit to mmHg and to_unit to atm, factor and atm_per_mmhg to the rounded exact conversion factor one over seven hundred sixty, mmhg_per_atm to the integer seven hundred sixty, formula to a short English equation string, message to a brief summary, and steps to an ordered array of substitution lines. Failed validation—missing fields, non-finite numbers, bare plus or minus signs, non-numeric strings, values outside absolute limits, or a non-finite converted result—returns invalid_input and is never charged. Pricing is a flat $0.002 per successful request with unit item.
Practical tips, checks, and related searches
Failed tasks that return invalid_input do not consume prepaid balance, which keeps exploratory scripts cheap when learners deliberately omit mmhg or pass text.
Technical questions
Is 760 mmHg per atmosphere exact?
Yes for this converter. Chemistry and engineering tables define 1 atm = 760 mmHg exactly. This capability hard-codes that conventional factor rather than a survey approximation.
What happens on invalid input?
Missing fields, non-finite numbers, or values outside the absolute limit return invalid_input. Failed tasks are never charged.