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How to use
Convert one pressure reading across common metric, engineering and atmospheric units using the pascal as the common base. Supported units include Pa, kPa, MPa, hPa, bar, mbar, psi, standard atmosphere, Torr, mmHg and inHg. For bar to psi, multiply by about 14.503773773; for psi to bar, multiply by about 0.068947573. Thus 2 bar is about 29.0075 psi and 30 psi is about 2.06843 bar. One standard atmosphere equals 1.01325 bar and 101.325 kPa.
- Enter the pressure reading and select its current unit.
- Choose the target pressure unit.
- See the target value plus quick equivalents in pascals, bar, psi and standard atmospheres.
How it is calculated
Example
Example: 1 bar = 100,000 Pa ≈ 14.503773773 psi ≈ 0.986923267 atm. One standard atmosphere is exactly 101,325 Pa by definition.
Important notes
This tool converts units only; it does not know whether a reading is absolute pressure or gauge pressure relative to ambient air. A negative gauge reading can therefore be converted mathematically but should not be treated as a negative absolute pressure. Torr and mmHg are very close but are kept as distinct definitions here.
Worked examples and interpreting results
A standard atmosphere is 101,325 Pa, while a bar is 100,000 Pa. These values are close but not identical, an important distinction when comparing pressure units.
| Case | Calculation | Result |
|---|---|---|
| One standard atmosphere | 1 atm × 101325 | 101,325 Pa |
| One bar in kilopascals | 100000 ÷ 1000 | 100 kPa |
How to check the result
Changing units does not convert gauge pressure into absolute pressure. That conversion needs the local atmospheric pressure or instrument reference. The meaning of a negative value also depends on the reference.
Pressure units: atm, bar, kPa and psi
Pressure unit conversions can be checked through pascals. One bar equals exactly 100,000 Pa; standard atmosphere equals exactly 101,325 Pa; one psi is about 6,894.76 Pa. Select source and target units before converting.
- Convert 1 bar to kilopascals: 100000 ÷ 1000 = 100 kPa
- Convert 1 standard atmosphere to kPa: 101325 ÷ 1000 = 101.325 kPa
- Convert 1 psi to kPa: 6894.757293 ÷ 1000 = ≈ 6.89476 kPa
Important distinction
Converting units does not change a gauge pressure into an absolute pressure. The reference pressure and measurement context matter, especially in technical applications.
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Frequently asked questions
How do I convert Torr to mmHg?
Enter the Torr value, select Torr as the source and mmHg as the target. The units are extremely close but use slightly different definitions, so the converter keeps them separate.
How many psi are in 1 bar?
About 14.503773773 psi.
Is 1 atm the same as 1 bar?
No. 1 atm is 101,325 Pa, while 1 bar is 100,000 Pa.
Are Torr and mmHg identical?
They are extremely close in ordinary use, but this converter keeps separate factors for the two definitions.
How do I convert psi to bar?
Multiply psi by about 0.068947573. For example, 30 psi is about 2.06843 bar. This changes units, not gauge pressure into absolute pressure.
How many bar are in 1 atm?
One standard atmosphere is exactly 1.01325 bar: 101325 Pa divided by 100000 Pa per bar.