Pressure unit conversion
1 atm is 14.695948775513 psi and 1 bar is exactly 100 kPa. Convert a reading between any two of Pa, kPa, bar, psi and atm so a datasheet, a gauge and a problem set agree. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Value
- 1
- From
- Atm
- To
- Psi
- Result
- 14.6959487755 psi
- Converted
- 14.6959487755
- Pascals
- 101,325
Pressure unit conversion is the everyday job of turning one finite reading into another label so a datasheet, a regulator, a manometer, and a problem set can agree. This tool accepts a finite numeric value plus source and target units among Pa, kPa, bar, psi, and atm, then returns the converted pressure through an exact pascal bridge. Zero maps to zero, identity conversions echo the rounded input, and the response always names the canonical target unit next to the converted magnitude.
Which pressure units this conversion uses and how the pascal bridge works
The SI coherent unit of pressure is the pascal: one newton per square metre. Engineering practice almost never stops at that coherent unit, which is why people search for pressure unit conversion rather than a single-pair calculator. Process sheets and many European tyre placards prefer the bar, defined as exactly one hundred thousand pascals.
Weather stations, HVAC gauges, and laboratory transducers often report kilopascals, one thousand pascals each. United States piping, compressor, and tyre work still quotes pounds per square inch, built from the international pound-force and the exact inch. Chemistry homework, scuba tables, and some aviation notes still use the standard atmosphere, fixed at exactly one hundred one thousand three hundred twenty-five pascals.
Converting among those five labels is a two-step identity: multiply the input by the exact factor that turns the source unit into pascals, then divide by the factor that turns pascals into the target unit. That identity is exact for Pa, kPa, bar, and atm. Zero maps to zero.
When from equals to, the conversion is an identity and returns the original finite number after stable twelve-decimal rounding. This landing does not convert millimetres of mercury, torr, inches of mercury, or metres of water; those queries belong to vacuum and manometer tools. Negative finite magnitudes are accepted because signed gauge deltas are still numbers; only missing fields, non-finite values, and unsupported unit labels are rejected.
Where pressure unit conversion earns its keep
Design notebooks jump between bar setpoints and psi nameplates on the same compressor skid; a single conversion call keeps the arithmetic out of a spreadsheet cell that someone will copy with the wrong factor. Chemistry and physics courses still mix atmospheres with kilopascals on gas-law worksheets, and a deterministic oracle that rejects torr here—because this page is not a mercury-column tool—stops a student from treating millimetres of mercury as if they were kilopascals.
Tyre and HVAC counters convert a metric kPa reading into psi for a customer who thinks in pounds, then convert back to check the placard. Automation scripts that ingest mixed vendor logs can normalize every finite reading to pascals, or to whatever target the downstream model expects, without pulling a general unit library for five labels. Failed validation does not consume balance, which keeps exploratory scripts cheap when learners omit from, send text, or try an unsupported unit on purpose.
Pin the rounded result in tests, document the factors one bar equals one hundred thousand pascals and one atmosphere equals one hundred one thousand three hundred twenty-five pascals next to the number, and you get reproducible pressure unit conversion for homework, CMS widgets, and edge workers without standing up a computer-algebra stack of your own.
What you can do with it
Datasheet and nameplate bridging
Turn a bar or kilopascal setpoint from a process sheet into psi (or the reverse) with the exact pascal bridge instead of a rounded classroom shortcut.
Homework and lab notebook checks
Convert atmospheres to kilopascals or pascals on gas-law problems and reject unsupported mercury units instead of silently guessing torr.
Log normalization in scripts
Normalize mixed Pa, kPa, bar, psi, and atm readings to one target unit in ingest pipelines without importing a general unit library.
FAQ
Which pressure units can I convert?
Pa, kPa, bar, psi, and atm. Send a finite value plus from and to from that closed set.
How is the conversion computed?
The value is multiplied by the exact pascals-per-source factor, then divided by the pascals-per-target factor. One bar is 1e5 Pa, one atmosphere is 101325 Pa, one kilopascal is 1000 Pa, and psi uses the international lbf/in² definition.
What happens if a unit is unsupported or the value is not finite?
The message names the field: missing or non-finite value, or an unrecognized from/to label such as torr.
Does 1 atm equal 14.7 psi here?
Approximately, after rounding. One standard atmosphere is exactly 101325 Pa; one psi is one international pound-force per square inch, so 1 atm converts to about 14.695948775513 psi, not a truncated 14.7.
Can I convert mmHg or torr here?
No. This converter covers only Pa, kPa, bar, psi and atm. Millimetres of mercury, torr, inches of mercury and metres of water belong to vacuum and manometer tools, so they are refused rather than guessed.
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/pressure-unit-conversion \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"value":1,"from":"atm","to":"psi"}'const res = await fetch("https://api.kit.forhosting.com/conv/pressure-unit-conversion", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"value": 1,
"from": "atm",
"to": "psi"
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/conv/pressure-unit-conversion",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"value": 1,
"from": "atm",
"to": "psi"
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/conv/pressure-unit-conversion", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"value":1,"from":"atm","to":"psi"}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"value":1,"from":"atm","to":"psi"}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/conv/pressure-unit-conversion", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"value": 1,
"from": "atm",
"to": "psi"
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "conv.pressure_unit_conversion",
"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
Unsupported unit names and non-finite magnitudes fail with invalid_input instead of inventing a number. Successful API calls are billed at $0.002 with unit item; validation failures are not billed.
Which pressure units this conversion uses and how the pascal bridge works
For psi the implementation uses the international definition of one pound-force per square inch so the Worker and the browser never disagree.
Input contract, response shape, and error behaviour
The closed set for both unit fields is Pa, kPa, bar, psi, and atm, so the web form can paint a select instead of asking visitors to memorise syntax. Unit labels are matched case-insensitively, so kilopascal, ATM, and psi all resolve to the canonical keys kPa, atm, and psi in the response. On success the body echoes the rounded value, the canonical from and to, result and converted as the same rounded target magnitude, unit as the canonical target token, pascals as the bridged SI value, and a short formula string restating the identity. Example: value one, from atm, to psi returns about fourteen point six nine six psi, because one standard atmosphere is one hundred one thousand three hundred twenty-five pascals and one psi is one pound-force per square inch. POST a JSON body with three required fields: value, a finite number for the pressure magnitude; from, the source unit; and to, the target unit. Aliases amount and pressure are accepted for value; source and unit_from for from; target and unit_to for to. Failed validation—missing fields, empty strings, NaN, Infinity, non-numeric text, values whose absolute magnitude exceeds one trillion, or a unit such as torr that this landing does not support—returns invalid_input naming the field and is never charged. Pricing is a flat $0.002 per successful request. Prefer bare JSON numbers when you control the client; numeric strings are accepted only when they match a strict finite pattern without embedded unit symbols.
Technical questions
What does pressure unit conversion cost?
The browser tool is free. API requests use prepaid KIT balance at $0.002 per successful call; invalid input is not billed.