Pressure Converter

Pressure is force per unit area — the SI unit is the pascal (Pa = N/m²), named for French scientist Blaise Pascal. This converter handles all major pressure units: SI metric (pascal, kilopascal, megapascal), atmospheric and meteorological (atmosphere = 101,325 Pa, bar = 100,000 Pa, millibar = hectopascal used on weather maps), American imperial (psi for tires and engineering, inch of mercury for aviation altimeters), medical (mmHg for blood pressure worldwide), and vacuum systems (torr essentially identical to mmHg). Reference values: atmospheric pressure at sea level is approximately 101.3 kPa (1 atm = 1.013 bar = 14.7 psi = 760 mmHg). Tire pressures range from 200–250 kPa (29–36 psi), blood pressure is healthy at about 120/80 mmHg, and industrial hydraulic systems operate at 10–70 MPa. Use pressure conversion for weather forecasting, tire inflation, medical diagnosis, hydraulic engineering, scuba diving, and scientific laboratory work.

The pascal is the base SI pressure unit, used in scientific publications and modern engineering specifications.

The kilopascal is the standard pressure unit on tire labels, weather forecasts, and modern engineering documents.

The megapascal is the engineering high-pressure unit, used in hydraulics, materials testing, and construction.

The bar is the everyday pressure unit in European tire pressures, hydraulics, and meteorology applications.

The millibar is the legacy meteorology unit, identical to hectopascal, still common in weather and aviation reports.

PSI (pounds per square inch) is the standard for American tire pressures, hydraulics, and gas-cylinder specifications.

The atmosphere equals average sea-level pressure and is used in chemistry, diving, and reference-condition contexts.

The millimeter of mercury is the standard medical unit for blood pressure measurements worldwide.

The torr equals one millimeter of mercury and is used in vacuum-system specifications and laboratory instruments.

The inch of mercury is the American aviation standard for altimeter settings and historic barometer readings.

• ✓1 bar = 100,000 Pa = almost 1 atmosphere. The bar is common in European weather and industry.
• ✓1 atmosphere = 101,325 Pa = 14.696 psi = 1013.25 mbar.
• ✓Car tyre pressure is typically 2.0–2.5 bar (29–36 psi, 200–250 kPa).
• ✓Blood pressure is measured in mmHg worldwide (e.g., 120/80 mmHg).

• ✗Confusing absolute and gauge pressure — gauge is relative to atmospheric, absolute is from zero.
• ✗Mixing psi and bar when setting tyre pressures — roughly 14.5 psi per bar.
• ✗Using mmHg for engineering (should be Pa, kPa or bar).
• ✗Assuming standard atmosphere is exactly 1 bar — it's 1.01325 bar.