Pressure unit converter
One standard atmosphere is 101325 Pa, 14.6959487755 psi and 760 mmHg. Enter a pressure in any of seven units, from pascals to torr, and read it in all seven at once for tire gauges, scuba tables, lab notes or weather reports. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Pressure magnitude to convert
- 1
- Input pressure unit
- atm
- Output pressure unit
- psi
- Result
- 14.6959487755
- Pascals
- 101,325
- Kilopascals
- 101.325
- Bars
- 1.01325
Pressure conversion between SI and customary units is a daily chore in HVAC specs, scuba tables, lab notebooks, tire gauges, weather reports, and process instrumentation. People search for a pressure converter when they need atmospheres next to kilopascals, psi next to bar, or torr next to mmHg, not a general multi-unit toolbox that also handles length and temperature. This capability accepts one finite amount plus from and to unit labels among pascal, kilopascal, bar, standard atmosphere, pounds per square inch, millimeters of mercury, and torr, bridges every conversion through the pascal so results stay consistent, and returns the target value together with the same pressure expressed in all seven units. Unrecognized unit names are rejected with a clear validation error instead of silently guessing a nearby symbol.
How the pressure converter maps SI and customary units through pascals
Start from the pascal as the SI unit of pressure, one newton per square metre, and express every other unit as a fixed factor into pascals. One kilopascal is exactly one thousand pascals, so the metric kilo step is a pure power of ten. One bar is defined as exactly one hundred thousand pascals, a convenient industrial scale near standard atmospheric pressure.
The standard atmosphere is fixed by definition at one hundred one thousand three hundred twenty-five pascals, so one atmosphere equals that exact constant without any temperature or altitude correction. One pound-force per square inch uses the conventional SI equivalent six thousand eight hundred ninety-four point seven five seven two nine three one six eight three six one pascals.
Torr is exactly one seven hundred sixtieth of a standard atmosphere, which equals one hundred one thousand three hundred twenty-five divided by seven hundred sixty pascals, and this calculator treats conventional millimetres of mercury as equal to torr so vacuum and medical blood-pressure style readings stay aligned with classroom and lab practice. The path is always amount times the source factor to reach pascals, then divide by the target factor.
Because every pair shares the same intermediate, converting one atmosphere to psi and then back, or comparing bar to kilopascals and torr, stays numerically consistent within ordinary floating-point precision. The tool does not apply gauge versus absolute offsets, does not convert hydrostatic depth into pressure, does not solve ideal-gas density from pressure and temperature, and does not fetch live weather station data.
It answers only the algebraic pressure unit conversion people mean when they type pressure converter into a search bar and expect Pa, kPa, bar, atm, psi, mmHg, and torr.
What you enter and what you get back
Send three fields: amount, a finite number for the pressure magnitude; from, a string naming the input unit; and to, a string naming the output unit. Both unit fields accept short keys and everyday words in any common casing, including pascal or pascals or Pa, kilopascal or kPa, bar or bars, atmosphere or atm, psi or pounds per square inch or psia, mmHg or millimeters of mercury, and torr.
When a unit string is unknown the error message includes Unrecognized unit and lists the seven supported families so clients can fix the label rather than guessing. Classic checks include one atmosphere becoming one hundred one point three two five kilopascals, one bar becoming one hundred kilopascals, one atmosphere becoming about fourteen point six nine six psi, seven hundred sixty torr becoming one atmosphere, and one thousand pascals becoming one kilopascal.
Where dedicated pressure conversion shows up in real work
Secondary-school and first-year engineering physics courses constantly assign problems that give a pressure on one scale and ask for another, often mixing atmospheres with pascals and psi with bar in the same worksheet. HVAC and process plants normalize sensor tags between bar, kPa, and psi before alarm limits and historian archives stay consistent across vendors. Medical and laboratory vacuum equipment often reports torr or mmHg while facility compressed-air lines are still labeled in bar or psi, so a single conversion pass keeps documentation and SCADA displays aligned.
Scuba and aviation tables still quote atmospheres and millimetres of mercury while modern dive computers and altimeters lean on kilopascals, and students need a ground-truth mapping without retyping constants. If you later need hydrostatic head from density and depth, ideal-gas density from pressure and temperature, or a general multi-category unit toolbox, treat those as separate search intents and landings rather than overloading this pressure converter page.
What you can do with it
Instrument tags and process limits
Normalize sensor and alarm pressures among Pa, kPa, bar, and psi so multi-vendor plant data and setpoints stay consistent.
Vacuum, lab, and medical scales
Convert torr and mmHg readings to atmospheres or pascals for lab notebooks, vacuum systems, and clinical documentation.
Physics homework and answer keys
Convert textbook pressures among atm, bar, psi, and kPa with one ground truth for grading and classroom demos.
FAQ
Which pressure units does this converter support?
Pascal (Pa), kilopascal (kPa), bar, standard atmosphere (atm), pounds per square inch (psi), millimeters of mercury (mmHg), and torr.
What happens if I send an unrecognized unit?
The error message includes Unrecognized unit and lists the supported families so you can correct the label.
Are torr and mmHg the same here?
Yes for this converter. Both use the exact torr definition 101325/760 Pa, which matches conventional classroom and engineering practice treating mmHg equal to torr.
What does it cost?
The browser tool is free and runs locally.
How many psi is one atmosphere?
One standard atmosphere is 14.6959487755 psi. The same pressure is 101325 Pa, 101.325 kPa, 1.01325 bar and 760 mmHg or torr, and the converter shows all of them together.
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 \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"amount":1,"from":"atm","to":"psi"}'const res = await fetch("https://api.kit.forhosting.com/conv/pressure", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"amount": 1,
"from": "atm",
"to": "psi"
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/conv/pressure",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"amount": 1,
"from": "atm",
"to": "psi"
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/conv/pressure", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"amount":1,"from":"atm","to":"psi"}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"amount":1,"from":"atm","to":"psi"}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/conv/pressure", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"amount": 1,
"from": "atm",
"to": "psi"
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "conv.pressure",
"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
What you send and what you get back from the API and browser form
Missing fields, non-numeric amount strings, NaN, Infinity, and unrecognized unit labels fail with invalid_input and are not charged. On success the response echoes the cleaned amount, normalized from and to keys, the primary result in the target unit, the same pressure as pascals, kilopascals, bars, atmospheres, psi, mmHg, and torr with twelve significant digits of stable precision, the SI factors used, the formula string, and method pascal_bridge. Pricing for successful API calls is the published base of $0.002 per item; validation failures do not consume prepaid balance.
Where dedicated pressure conversion shows up in real work
Data pipelines that ingest mixed IoT or MES payloads with Pa, bar, and psi tags can call this capability once per reading instead of reimplementing the factors in every service. Because this capability is a pure parse engine, API pricing is the published base of $0.002 per successful item and failed validation does not consume balance.
Technical questions
Does it handle gauge pressure (psig) versus absolute (psia)?
No gauge offset is applied. Labels such as psig and psia are accepted as magnitude aliases for psi only; add or subtract atmospheric offset yourself if your problem requires absolute versus gauge.