Pressure Converter
Convert pressure between pascal, bar, psi, atmosphere, torr, mmHg and many other units. Choose two units, enter a value and read the answer.
Select two units to see the conversion factor.
This tool converts units of pressure. It does not change absolute pressure into gauge pressure, because that needs the air pressure around you.
Pressure Formula
Every pressure unit is a fixed multiple of the pascal (1 Pa = 1 N/m²). Result = value × (size of source unit in Pa ÷ size of target unit in Pa). Exact sizes: 1 bar = 100,000 Pa, 1 atm = 101,325 Pa, 1 torr = 101,325/760 Pa, 1 kgf/cm² = 98,066.5 Pa and 1 psi = 6,894.757293168 Pa (one pound-force on one square inch).
What Is Pressure?
Pressure is force spread over an area: pressure = force ÷ area. The SI unit is the pascal (Pa), one newton on one square meter. A pascal is small, so kilopascal (kPa), megapascal (MPa) and bar are more common.
The units fall into groups. SI and metric: pascal with its prefixes, bar, millibar, N/m², N/mm². Atmosphere units: the standard atmosphere (101,325 Pa) and the technical atmosphere (1 kgf/cm²). Engineering units: psi, ksi, pound-force per square foot and ton-force units. Column units: torr, millimeter of mercury, inch of mercury and inches or feet of water, used for weather, medicine and ventilation.
Absolute and gauge pressure. Absolute pressure is measured from a perfect vacuum. Gauge pressure is measured against the air around you. A car tire at “32 psi” is usually 32 psi gauge, which is about 46.7 psi absolute at sea level. This converter changes units only and does not add or remove the air pressure. If your source says psig or barg, it is gauge pressure, and the result keeps that same meaning.
Mercury and water columns. These units depend on the temperature and gravity used in their definition, which is why the temperature is written next to them, for example inch of mercury (32 °F) and inch of water (4 °C). Torr and mmHg are almost, but not exactly, equal.
Supported Units
This converter supports the following 50 pressure units. The last column gives the size of each unit in pascals. Mercury and water column units are conventional values with limited accuracy, so their last digits should not be over-trusted.
| Unit | Symbol | Value in Pa |
|---|---|---|
| Pascal | Pa | 1 |
| Exapascal | EPa | 1e+18 |
| Petapascal | PPa | 1e+15 |
| Terapascal | TPa | 1e+12 |
| Gigapascal | GPa | 1,000,000,000 |
| Megapascal | MPa | 1,000,000 |
| Kilopascal | kPa | 1,000 |
| Hectopascal | hPa | 100 |
| Dekapascal | daPa | 10 |
| Decipascal | dPa | 0.1 |
| Centipascal | cPa | 0.01 |
| Millipascal | mPa | 0.001 |
| Micropascal | µPa | 1e-6 |
| Nanopascal | nPa | 1e-9 |
| Picopascal | pPa | 1e-12 |
| Femtopascal | fPa | 1e-15 |
| Attopascal | aPa | 1e-18 |
| Bar | bar | 100,000 |
| Millibar | mbar | 100 |
| Microbar | µbar | 0.1 |
| Standard atmosphere | atm | 101,325 |
| Technical atmosphere | at | 98,066.5 |
| Pound-force per square inch | psi | 6,894.757293 |
| Kip-force per square inch | ksi | 6,894,757.293 |
| Pound-force per square foot | lbf/ft² | 47.88025898 |
| Poundal per square foot | pdl/ft² | 1.488163944 |
| Ton-force (short) per square foot | tonf/ft² | 95,760.51796 |
| Ton-force (short) per square inch | tonf/in² | 13,789,514.59 |
| Ton-force (long) per square foot | ltonf/ft² | 107,251.7801 |
| Ton-force (long) per square inch | ltonf/in² | 15,444,256.34 |
| Newton per square meter | N/m² | 1 |
| Newton per square centimeter | N/cm² | 10,000 |
| Newton per square millimeter | N/mm² | 1,000,000 |
| Kilonewton per square meter | kN/m² | 1,000 |
| Dyne per square centimeter | dyn/cm² | 0.1 |
| Kilogram-force per square meter | kgf/m² | 9.80665 |
| Kilogram-force per square centimeter | kgf/cm² | 98,066.5 |
| Kilogram-force per square millimeter | kgf/mm² | 9,806,650 |
| Gram-force per square centimeter | gf/cm² | 98.0665 |
| Torr | Torr | 133.3223684 |
| Millimeter of mercury (0 °C, conventional) | mmHg | 133.3223874 |
| Centimeter of mercury (0 °C, conventional) | cmHg | 1,333.223874 |
| Inch of mercury (32 °F) | inHg (32 °F) | 3,386.389 |
| Inch of mercury (60 °F) | inHg (60 °F) | 3,376.85 |
| Millimeter of water (4 °C) | mmH₂O (4 °C) | 9.80638 |
| Centimeter of water (4 °C) | cmH₂O (4 °C) | 98.0638 |
| Inch of water (4 °C) | inH₂O (4 °C) | 249.082 |
| Foot of water (4 °C) | ftH₂O (4 °C) | 2,988.98 |
| Inch of water (60 °F) | inH₂O (60 °F) | 248.843 |
| Foot of water (60 °F) | ftH₂O (60 °F) | 2,986.116 |
How to Use the Pressure Converter
- Type the pressure in the value box. Decimals and scientific notation such as 0.0025 or 2.5e-3 are accepted.
- Choose the From unit and the To unit.
- The result appears instantly, or press Convert Now. Very large or very small results are shown in scientific notation.
- Use Swap Units to reverse the conversion, Copy Result to copy the answer, open Show this value in all units for a full list, and Clear to start again.
Step-by-step by hand
- Find the size of each unit in the common base unit (Pa): 1 bar = 100,000 Pa and 1 psi = 6,894.757293 Pa.
- Divide the source size by the target size to get the conversion factor: 100,000 ÷ 6,894.757293 = 14.50377377, so 1 bar = 14.50377377 psi.
- Multiply by your value: 2.2 bar × 14.50377377 = 31.9083023 psi.
Pressure values are not negative here. For a vacuum reading, use the absolute pressure instead.
Common Pressure Conversions
- Tire pressure: 2.2 bar equals 31.9083023 psi, and 32 psi equals 2.206322334 bar.
- Air pressure: 1 standard atmosphere equals 1,013.25 hPa and 14.69594878 psi.
- Weather: 1013.25 mbar equals 29.9212524 inHg.
- Blood pressure: 120 mmHg equals 15.99868649 kPa.
- Hydraulics: 250 bar equals 25 MPa and 3,625.943443 psi.
- Material strength: 50 ksi equals 344.7378647 MPa.
- Old gauges: 1 kgf/cm² equals 0.980665 bar.
- Ventilation: 1 inch of water (4 °C) equals 249.082 Pa.
Bar to Other Pressure Units
Quick reference for frequently used values
| bar | kPa | psi | atm |
|---|---|---|---|
| 0.5 | 50 | 7.251886887 | 0.4934616334 |
| 1 | 100 | 14.50377377 | 0.9869232667 |
| 2 | 200 | 29.00754755 | 1.973846533 |
| 2.5 | 250 | 36.25943443 | 2.467308167 |
| 5 | 500 | 72.51886887 | 4.934616334 |
| 10 | 1,000 | 145.0377377 | 9.869232667 |
| 100 | 10,000 | 1,450.377377 | 98.69232667 |
| 250 | 25,000 | 3,625.943443 | 246.7308167 |
Where and Why This Conversion Is Used
- Vehicles: tire pressure in bar, kPa or psi.
- Weather: hPa, mbar and inHg.
- Medicine: mmHg for blood pressure.
- Industry and hydraulics: bar, MPa and psi on pumps, tanks and compressors.
- Diving and aviation: bar, atm and inHg.
- Engineering: ksi and MPa for material strength.
Important Limitations
- The tool does not convert between absolute and gauge pressure. Do not treat them as the same.
- Standard atmosphere (101,325 Pa) is a fixed value. Real air pressure changes with weather and height.
- Mercury and water column units depend on temperature and gravity. The listed value is a conventional one.
- Pressure is not the same as force. A force in newtons needs an area before it becomes a pressure.