Pressure Unit Converter | Pa, kPa, bar, atm, psi, mmHg, torr

Converting between pressure units is simple with our tool:

1. Enter the pressure value you want to convert in the "Value" field
2. Select the unit you're converting from in the "From" dropdown
3. Click "Convert" (or the conversion happens automatically)
4. View all equivalent values in different units in the "Converted values" section

For example, to convert 2 atmospheres (atm) to psi, enter "2" in the value field, select "atm" from the dropdown, and the tool will show you that 2 atm equals 29.392 psi along with conversions to all other pressure units.

Different pressure units have various origins and applications:

• Pascal (Pa) - The SI unit for pressure, defined as one newton per square meter (N/m²)
• Kilopascal (kPa) - 1,000 pascals, commonly used in meteorology and engineering
• Bar - Approximately equal to atmospheric pressure at sea level (1 bar = 100,000 Pa)
• Atmosphere (atm) - Based on standard atmospheric pressure at sea level (1 atm = 101,325 Pa)
• Millimeter of mercury (mmHg) - The pressure exerted by a 1mm column of mercury, used in medicine for blood pressure
• Torr - Nearly identical to mmHg, named after Evangelista Torricelli, used in vacuum technology
• Pounds per square inch (psi) - Common in US/UK engineering, automotive, and industrial applications

Each unit is preferred in different fields; scientists typically use pascals, engineers often use bar or psi, and medical professionals use mmHg.

Atmospheric pressure is the force exerted by the weight of air in the atmosphere of Earth. Standard atmospheric pressure (at sea level, 15°C) is defined as:

• 101,325 pascals (Pa)
• 101.325 kilopascals (kPa)
• 1.01325 bar
• 1 atmosphere (atm)
• 760 millimeters of mercury (mmHg)
• 760 torr
• 14.696 pounds per square inch (psi)

Atmospheric pressure decreases with altitude. At 1,000 meters (3,281 feet) above sea level, atmospheric pressure is about 90 kPa, and at 10,000 meters (commercial aircraft cruising altitude), it's only about 26 kPa. Atmospheric pressure also varies with weather conditions - high pressure systems typically bring fair weather, while low pressure systems often bring storms and precipitation.

Pressure units are used in many common applications:

• Tire pressure - Measured in psi in the US/UK and bar or kPa in most other countries
• Blood pressure - Measured in mmHg (e.g., 120/80 mmHg)
• Weather forecasting - Atmospheric pressure reported in millibars, hPa, or inches of mercury
• Scuba diving - Tank pressure in psi or bar; depth pressure increases by approximately 1 atm per 10 meters
• Industrial processes - Operating pressures for equipment often specified in bar, kPa, or psi
• Cooking - Pressure cookers typically operate at 15 psi (1 bar) above atmospheric pressure
• HVAC systems - Refrigerant pressures monitored in psi or bar

This converter is particularly useful for engineers working across different unit systems, scientists comparing measurements from different sources, and students learning about pressure in various contexts.

This pressure unit converter uses precise conversion factors based on internationally accepted standards. The conversions are mathematically exact with factors like:

• 1 bar = 100,000 Pa exactly
• 1 atm = 101,325 Pa exactly
• 1 mmHg = 133.322 Pa (rounded to 6 significant figures)
• 1 psi = 6,894.76 Pa (rounded to 6 significant figures)

The calculator displays results with appropriate significant figures based on the magnitude of the value, using scientific notation for very large or small numbers. For practical engineering and scientific applications, these conversions provide more than sufficient accuracy, typically to at least 6 significant figures.