Pressure Converter
Convert between pascals, bar, PSI, atmospheres, torr, and other pressure units.
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How to use this calculator
- 1
Enter your pressure value in the "From" field.
- 2
Select the unit you are converting from (e.g. PSI).
- 3
Select the target unit (e.g. bar).
- 4
The result appears instantly.
Frequently asked questions
How many psi are in a bar?
One bar is 100,000 Pa, which is 14.50377377 psi. Conversely, 1 psi is 0.068947573 bar or 6,894.757293 Pa. A tyre pressure of 2.2 bar is 31.9083023 psi, and 35 psi is 2.413165053 bar.
Is an atmosphere the same as a bar?
Close, but not equal. One standard atmosphere is exactly 101,325 Pa, i.e. 1.01325 bar, 760 torr or 14.69594878 psi. The bar is exactly 100,000 Pa, so 1 bar is 0.98692327 atm.
Are torr and mmHg the same?
The tool lists them as one entry and defines the torr as exactly 1/760 of an atmosphere, 133.3223684 Pa. A millimetre of mercury is defined from mercury density and gravity and differs from the torr only beyond the seventh significant digit, far below measurement accuracy. Blood pressure of 120 mmHg is 15.99868421 kPa here.
What is the difference between a millibar and a hectopascal?
None: 1 mbar is 100 Pa, which is 1 hPa. Weather maps use either name. Standard atmospheric pressure is 1,013.25 mbar, equal to 29.9212524 inHg. Note that the commonly quoted 29.92 inHg is a rounded figure; it comes out as 1,013.207589 mbar.
Does it separate gauge and absolute pressure?
No. It converts the number you enter as given. A tyre gauge reads pressure above the surrounding air, and absolute pressure adds about one atmosphere (14.69594878 psi at sea level). Add or subtract the ambient pressure yourself before and after converting.
How precise are the factors?
The pascal, bar, atmosphere and torr are exact definitions, and the psi uses 6,894.757293168 Pa, which comes from the pound-force and the inch. The inch of mercury uses the conventional 3,386.389 Pa. Display is about ten significant digits.
When should I use kPa, MPa or bar?
The tool lists them all: 1 kPa is 1,000 Pa, 1 MPa is 1,000,000 Pa, which is exactly 10 bar and 145.0377377 psi. Choose the unit the document uses; a 200 bar cylinder is 20 MPa and 2,900.754755 psi.
Pressure units: pascals, bar, psi, atmospheres and mmHg
Every unit is defined from the pascal
A pascal is one newton per square metre. The bar is exactly 100,000 Pa and the standard atmosphere exactly 101,325 Pa. The torr is 1/760 of an atmosphere, 133.3223684 Pa. A psi, pound-force per square inch, is 6,894.757293 Pa, and an inch of mercury is 3,386.389 Pa on the conventional definition. The converter passes everything through pascals using these values. The pascal is a very small unit, so practical work uses kilopascals, megapascals, bar or psi instead.
Reference values taken from the converter
Each row begins with one pressure unit and shows the same pressure in pascals, bar, psi and torr, copied from the tool’s output.
| From | Pa | bar | psi | Torr |
|---|---|---|---|---|
| 1 atm | 101,325 | 1.01325 | 14.69594878 | 760 |
| 1 bar | 100,000 | 1 | 14.50377377 | 750.0616827 |
| 1 psi | 6,894.757293 | 0.068947573 | 1 | 51.71493257 |
| 1 kPa | 1,000 | 0.01 | 0.14503774 | 7.500616827 |
| 1 inHg | 3,386.389 | 0.03386389 | 0.4911542 | 25.40000632 |
| 1 mbar | 100 | 0.001 | 0.014503774 | 0.75006168 |
Worked examples: tyres, weather and cylinders
A 32 psi tyre holds 220.6322334 kPa, or 2.206322334 bar. A 2.2 bar tyre is 31.9083023 psi. Standard air pressure of 1,013.25 mbar corresponds to 1 atm and 29.9212524 inHg. A 200 bar gas cylinder is 20 MPa, or 2,900.754755 psi. A blood pressure of 120 mmHg is 15.99868421 kPa. In everyday terms, 1 atm is 101.325 kPa, so a reading of 101.325 kPa is the same as 14.69594878 psi, 1.01325 bar and 760 torr: a quick cross-check of any answer.
Gauge pressure versus absolute pressure
Gauges usually show pressure above the surrounding atmosphere (gauge pressure), while physics and weather work with absolute pressure. At sea level they differ by about 14.69594878 psi. This tool does not know which one you have: it multiplies by a factor and nothing else, so adjust for ambient pressure on your own when comparing. Absolute and gauge readings are labelled psia and psig in much industrial work, and bar(g) and bar(a) elsewhere.
What the converter does not do
It does not convert pressure to force (that needs an area), or to altitude, depth or boiling point. Vacuum levels in torr work as simple pressures. Rounding to ten significant digits is cosmetic, and real gauges typically resolve far fewer. Pressure is also not the same as vacuum depth or suction rating, which come with their own reference conventions.
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Results are estimates for informational purposes only and do not constitute professional financial, medical, legal, or technical advice. Read full disclaimer →