UnitSnapPressure converter
Pressure is force applied per unit area. The SI unit is the pascal (Pa), equal to one newton per square meter. Because the pascal is small, kilopascals and megapascals are common in engineering, and the hectopascal, identical to the millibar, is the standard unit in weather reports.
Convert between 18 pressure units. Pick any two units below; results update as you type.
Popular pressure conversions
- Pounds per Square Inch to Bar
- Bar to Pounds per Square Inch
- Pounds per Square Inch to Kilopascals
- Kilopascals to Pounds per Square Inch
- Bar to Kilopascals
- Kilopascals to Bar
- Bar to Standard Atmospheres
- Standard Atmospheres to Bar
- Standard Atmospheres to Pounds per Square Inch
- Pounds per Square Inch to Standard Atmospheres
- Millimeters of Mercury to Kilopascals
- Kilopascals to Millimeters of Mercury
- Kilograms-Force per Square Centimeter to Pounds per Square Inch
- Pounds per Square Inch to Kilograms-Force per Square Centimeter
- Inches of Mercury to Hectopascals
- Hectopascals to Inches of Mercury
- Megapascals to Pounds per Square Inch
- Pounds per Square Inch to Megapascals
- Pascals to Pounds per Square Inch
- Pounds per Square Inch to Pascals
About pressure units
The bar is exactly 100 kPa, and standard atmosphere (atm) is exactly 101.325 kPa. In the United States, tire and gas pressures are given in psi (pounds-force per square inch), and material strength often in ksi (thousands of psi). Blood pressure uses millimeters of mercury, and low-pressure ventilation work uses inches or millimeters of water.
The torr is defined as exactly 1/760 of a standard atmosphere and is very nearly equal to one millimeter of mercury. The kilogram-force per square centimeter, sometimes called the technical atmosphere, is exactly 98.0665 kPa and still appears on older gauges.
Tips
- Tire gauges show gauge pressure (above atmospheric), while many scientific values are absolute; add about 101 kPa (about 14.7 psi) to gauge pressure to get absolute.
- One bar is close to, but not the same as, one atmosphere; the difference is about 1.3%.
- Weather maps use hPa or mbar, which are identical, while US broadcasts often use inches of mercury.
All pressure units
| Unit | Symbol | Value in standard atmospheres |
|---|---|---|
| Standard Atmospheres | atm | 1 atm = 1 atm |
| Pascals | Pa | 1 Pa = 0.000009869233 atm |
| Hectopascals | hPa | 1 hPa = 0.0009869233 atm |
| Kilopascals | kPa | 1 kPa = 0.009869233 atm |
| Megapascals | MPa | 1 MPa = 9.869233 atm |
| Bar | bar | 1 bar = 0.9869233 atm |
| Pounds per Square Inch | psi | 1 psi = 0.06804596 atm |
| Pounds per Square Foot | psf | 1 psf = 0.0004725414 atm |
| Kips per Square Inch | ksi | 1 ksi = 68.04596 atm |
| Kilograms-Force per Square Centimeter | kgf/cm² | 1 kgf/cm² = 0.9678411 atm |
| Kilograms-Force per Square Meter | kgf/m² | 1 kgf/m² = 0.00009678411 atm |
| Millimeters of Mercury | mmHg | 1 mmHg = 0.001315789 atm |
| Centimeters of Mercury | cmHg | 1 cmHg = 0.01315789 atm |
| Inches of Mercury | inHg | 1 inHg = 0.03342106 atm |
| Millimeters of Water | mmH₂O | 1 mmH₂O = 0.00009678411 atm |
| Centimeters of Water | cmH₂O | 1 cmH₂O = 0.0009678411 atm |
| Inches of Water | inH₂O | 1 inH₂O = 0.002458316 atm |
| Millitorrs | mTorr | 1 mTorr = 0.000001315789 atm |
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Factors: NIST SP 811 · SI Brochure · NIST Handbook 44 — Updated