Pressure Converter
Use this free Pressure Converter to convert pressure measurements between PSI, bar, kPa, MPa, Pa, atm, mmHg, Torr, inHg, kgf/cm², kgf/m², cmH₂O, mH₂O, inH₂O and many other pressure units.
The calculator is designed for engineering, mechanical systems, hydraulics, pneumatics, automotive applications, HVAC, industrial equipment, weather measurements, scientific work and everyday pressure calculations.
Quick Pressure Conversions
What Is Pressure?
Pressure is the amount of force applied perpendicular to a surface divided by the area over which the force acts. Pressure is commonly used to describe the force exerted by gases, liquids and solids.
The SI unit of pressure is the pascal, abbreviated as Pa. One pascal is equal to one newton per square meter.
Pressure Units Supported
Smart Unit Calc supports metric, imperial, engineering, scientific, atmospheric, mercury-column and water-column pressure units.
| Pressure Unit | Symbol | Definition / Reference |
|---|---|---|
| Pascal | Pa | 1 Pa |
| Kilopascal | kPa | 1,000 Pa |
| Megapascal | MPa | 1,000,000 Pa |
| Gigapascal | GPa | 1,000,000,000 Pa |
| Bar | bar | 100,000 Pa |
| Millibar | mbar | 100 Pa |
| Hectopascal | hPa | 100 Pa |
| Standard Atmosphere | atm | 101,325 Pa |
| Pound-force per Square Inch | psi | 6,894.757293168 Pa |
| Pound-force per Square Foot | psf | 47.88025898033584 Pa |
| Torr | Torr | Approximately 133.322368 Pa |
| Millimeter of Mercury | mmHg | Approximately 133.322387 Pa |
| Centimeter of Mercury | cmHg | Approximately 1,333.22387 Pa |
| Inch of Mercury | inHg | Approximately 3,386.389 Pa |
| Kilogram-force per cm² | kgf/cm² | Approximately 98,066.5 Pa |
| Kilogram-force per m² | kgf/m² | Approximately 9.80665 Pa |
| Meter of Water | mH₂O | Approximately 9,806.65 Pa |
| Centimeter of Water | cmH₂O | Approximately 98.0665 Pa |
| Millimeter of Water | mmH₂O | Approximately 9.80665 Pa |
| Inch of Water | inH₂O | Approximately 249.0889 Pa |
PSI Pressure Converter
PSI means pounds per square inch. It is one of the most widely used pressure units in the United States and is also commonly encountered internationally in automotive, industrial and mechanical applications.
PSI to Bar
To convert PSI to bar, multiply the pressure in PSI by approximately 0.0689475729.
Example:
Bar to PSI
Example:
PSI to kPa
Example:
kPa to PSI
Example:
MPa Pressure Converter
The megapascal (MPa) is commonly used for high-pressure engineering applications, hydraulic systems, pressure vessels, industrial equipment and material specifications.
1 MPa = 10 bar
1 MPa ≈ 145.037738 psi
Bar Pressure Converter
The bar is a widely used metric pressure unit, especially in engineering, industrial equipment, compressors, pumps and automotive applications.
1 bar = 100 kPa
1 bar ≈ 14.5037738 psi
kPa Pressure Converter
Kilopascals are commonly used for atmospheric pressure, tire pressure, HVAC systems, building services and engineering measurements.
1 bar = 100 kPa
1 atm = 101.325 kPa
Atmospheric Pressure Converter
Standard atmosphere, abbreviated as atm, is a reference pressure unit based on standard atmospheric pressure at sea level.
1 atm = 101.325 kPa
1 atm = 1.01325 bar
1 atm ≈ 14.6959488 psi
mmHg Pressure Converter
Millimeters of mercury (mmHg) are commonly used in pressure measurement, especially in medical and scientific applications.
Torr Pressure Converter
Torr is a pressure unit commonly associated with vacuum measurements and scientific applications.
1 Torr ≈ 133.322368 Pa
Inches of Mercury Converter
Inches of mercury, written as inHg, are commonly used for atmospheric pressure, vacuum gauges, weather measurements and aviation-related applications.
Water Column Pressure Converter
Water-column units such as mmH₂O, cmH₂O, mH₂O and inH₂O are commonly used for low-pressure measurements in HVAC, ventilation, gas systems, air filters and industrial equipment.
1 cmH₂O ≈ 98.0665 Pa
1 mmH₂O ≈ 9.80665 Pa
1 inH₂O ≈ 249.0889 Pa
kgf/cm² Pressure Converter
Kilogram-force per square centimeter, commonly written as kgf/cm² or kg/cm² in some technical contexts, is a legacy engineering pressure unit that may still appear on equipment specifications and gauges.
1 kgf/cm² ≈ 14.223343 psi
Common Pressure Conversion Chart
| Pressure | Equivalent |
|---|---|
| 1 Pa | 1 Pa |
| 1 kPa | 1,000 Pa |
| 1 bar | 100 kPa |
| 1 bar | 14.5037738 psi |
| 1 psi | 6.894757293 kPa |
| 1 MPa | 10 bar |
| 1 MPa | 145.037738 psi |
| 1 atm | 101.325 kPa |
| 1 atm | 14.6959488 psi |
| 1 Torr | Approximately 133.322 Pa |
| 1 inHg | Approximately 3.386 kPa |
| 1 kgf/cm² | Approximately 98.0665 kPa |
Pressure Converter for Engineering
Pressure conversion is important in mechanical engineering, civil engineering, chemical processing, manufacturing and industrial plant operations. Engineers may encounter pressure specifications in Pa, kPa, MPa, bar, psi, kgf/cm² and other units.
Pressure Converter for Hydraulics
Hydraulic systems commonly operate at high pressures and may use MPa, bar or PSI depending on the equipment manufacturer and region. Converting between these units helps compare hydraulic pumps, cylinders, valves and pressure ratings.
Pressure Converter for Pneumatics
Pneumatic systems commonly use bar, kPa or PSI. Pressure conversion is useful when selecting compressors, pneumatic tools, actuators, regulators and air-treatment equipment.
Pressure Converter for Tire Pressure
Tire pressure may be displayed in PSI, kPa or bar depending on the vehicle and country. Use the converter to compare tire pressure recommendations between different units.
Pressure Converter for HVAC
HVAC and ventilation systems frequently use Pa, kPa, inH₂O and mmH₂O for measuring air pressure, duct pressure, filter pressure drop and fan performance.
Pressure Converter for Vacuum
Vacuum measurements can be expressed using Torr, mmHg, inHg, Pa, kPa and other units. Always identify whether a pressure measurement is absolute pressure, gauge pressure or differential pressure before comparing values.
Absolute Pressure vs Gauge Pressure
Pressure measurements can have different reference points. Absolute pressure is measured relative to a perfect vacuum, while gauge pressure is measured relative to the surrounding atmospheric pressure.
Pressure Formula
The basic physical formula for pressure is force divided by area.
Where:
- P = pressure
- F = perpendicular force
- A = surface area
How to Use the Pressure Converter
- Enter the pressure value.
- Select the original pressure unit.
- Select the unit you want to convert to.
- Click Convert or allow automatic conversion.
- Use Swap Units to reverse the conversion.
- Click Copy Result to copy the answer.
Pressure Conversion Accuracy
The calculator uses standard conversion factors and the pascal as its internal base unit. Results may display more decimal places than are appropriate for a particular measuring instrument, so practical engineering results should normally be rounded according to the required measurement precision.
Units such as mmHg, Torr, inHg and water-column pressure can have reference definitions or conventions that differ slightly. For technical or regulated applications, always confirm the pressure-unit definition required by the applicable standard, instrument or specification.
Frequently Asked Questions About Pressure Conversion
How many PSI are in 1 bar?
1 bar is approximately 14.5037738 PSI.
How many kPa are in 1 PSI?
1 PSI is approximately 6.894757293 kPa.
How many PSI are in 1 MPa?
1 MPa is approximately 145.037738 PSI.
How many kPa are in 1 bar?
1 bar equals exactly 100 kPa.
How many bar are in 100 PSI?
100 PSI is approximately 6.894757 bar.
How many PSI are in 1 atmosphere?
One standard atmosphere is approximately 14.6959488 PSI.
What is the SI unit of pressure?
The SI unit of pressure is the pascal (Pa), equal to one newton per square meter.
What is the difference between PSI and bar?
PSI and bar are different pressure units. One bar equals approximately 14.5038 PSI.
What is 1 MPa equal to in bar?
1 MPa equals 10 bar.
What is 1 bar equal to in kPa?
1 bar equals 100 kPa.
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