Convert Pressure
Convert pressure measurements between different units quickly and accurately
Pressure Conversion Calculator
Popular Pressure Conversions
Quickly convert between the most commonly used pressure units.
Understanding Pressure Measurements
Pressure conversions are essential for various applications, from engineering and physics to everyday measurements, weather forecasting, medical applications, and industrial processes. Understanding pressure conversions across all measurement systems ensures accurate and consistent results in any field.
Common Pressure Units
SI/Metric Units
- Pascal (Pa) - SI base unit
- Kilopascal (kPa) - Common engineering
- Megapascal (MPa) - High pressure systems
- Hectopascal (hPa) - Meteorology
- Millibar (mbar) - Weather pressure
- Bar (bar) - Industrial standard
Force-Based Units
- Kilogram-force per cm² (kgf/cm²) - Automotive
- Gram-force per cm² (gf/cm²) - Laboratory
- Kilogram-force per m² (kgf/m²) - Construction loads
Imperial/US Units
- Pounds per Square Inch (psi) - Common
- Kilopounds per Square Inch (ksi) - Industrial
- Pounds per Square Foot (psf) - Construction
- Atmosphere (atm) - Reference standard
Mercury-Based Units
- Millimeters of Mercury (mmHg) - Medical
- Centimeters of Mercury (cmHg) - High pressure medical
- Inches of Mercury (inHg) - Weather/barometric
- Torr (torr) - Vacuum systems
Common Applications
| Field | Typical Units | Pressure Range |
|---|---|---|
| Weather/Meteorology | mbar, hPa, inHg | 980-1050 mbar |
| Medical/Blood Pressure | mmHg, cmHg | 80-180 mmHg |
| Automotive/Tires | psi, bar, kgf/cm² | 25-40 psi, 2.1-2.5 kgf/cm² |
| Industrial Hydraulics | MPa, ksi, kgf/cm² | 10-350 MPa |
| Construction Loads | psf, kPa, kgf/m² | 20-100 psf, 1000-4800 kgf/m² |
| Vacuum Systems | torr, Pa | 0.001-760 torr |
| Engineering/Physics | Pa, kPa, MPa | 1 Pa - 1000 MPa |
| Laboratory | mmHg, torr, kPa, gf/cm² | 1-1000 torr, 1-1000 gf/cm² |
| European/Asian Industry | kgf/cm², bar | 1-100 kgf/cm² |
Conversion Tips
- Weather: 1 mbar = 1 hPa (exactly equivalent units)
- Standard atmospheric pressure: 1013.25 mbar/hPa = 29.92 inHg = 1.033 kgf/cm²
- For quick estimates: 1 atmosphere ≈ 1 bar ≈ 14.7 psi ≈ 1.03 kgf/cm²
- Automotive: 1 kgf/cm² ≈ 0.98 bar ≈ 14.22 psi (tire pressure)
- Industrial high pressure: 1 MPa = 145 psi = 1000 kPa = 10.2 kgf/cm²
- Construction: 1 psi = 144 psf, 1 kgf/cm² = 10,000 kgf/m²
- Laboratory: 1 gf/cm² = 98.07 Pa = 0.001 kgf/cm²
- Medical: Normal blood pressure ~120/80 mmHg = 16/10.7 kPa = 0.163/0.109 kgf/cm²
- Mercury units: 1 cmHg = 10 mmHg = 1.33 kPa = 0.0136 kgf/cm²
- Vacuum: Perfect vacuum = 0 Pa absolute pressure
Pressure Conversions
| Conversion | Formula/Rule | Quick Answer |
|---|---|---|
| mbar to hPa | 1 mbar = 1 hPa | Exactly equal |
| kgf/cm² to bar | 1 kgf/cm² = 0.98067 bar | Multiply kgf/cm² by 0.98 |
| kgf/cm² to psi | 1 kgf/cm² = 14.223 psi | Multiply kgf/cm² by 14.2 |
| bar to kgf/cm² | 1 bar = 1.0197 kgf/cm² | Multiply bar by 1.02 |
| psi to kgf/cm² | 1 psi = 0.0703 kgf/cm² | Multiply psi by 0.07 |
| gf/cm² to Pa | 1 gf/cm² = 98.07 Pa | Multiply gf/cm² by 98 |
| kgf/m² to psf | 1 kgf/m² = 0.2048 psf | Multiply kgf/m² by 0.2 |
| MPa to psi | 1 MPa = 145.04 psi | Multiply MPa by 145 |
| ksi to MPa | 1 ksi = 6.895 MPa | Multiply ksi by 6.9 |
| psi to psf | 1 psi = 144 psf | Multiply psi by 144 |
| cmHg to mmHg | 1 cmHg = 10 mmHg | Multiply cmHg by 10 |
| atm to hPa | 1 atm = 1013.25 hPa | Multiply atm by 1013.25 |
Our comprehensive pressure conversion tool covers all major pressure units from millibar weather measurements to megapascal industrial applications, including metric force units like kgf/cm² commonly used in automotive and European/Asian engineering. Whether you're working in meteorology, medicine, engineering, construction, automotive, or scientific research, our converter provides accurate conversions for any pressure-related calculation.
Pressure Conversion Questions
Everything you need to know about pressure measurements and conversions
What's the difference between gauge and absolute pressure?
Gauge pressure measures pressure relative to atmospheric pressure (0 psi gauge = 14.7 psi absolute at sea level). Absolute pressure measures pressure relative to a perfect vacuum (0 psi absolute = perfect vacuum). Most pressure measurements in everyday use are gauge pressure. For example, a car tire at 30 psi gauge contains 44.7 psi absolute pressure.
Why are there so many pressure units?
Different pressure units evolved for different applications and regions. Engineers use pascals (SI standard), meteorologists use millibars/hectopascals, Americans use psi, Europeans often use bar or kgf/cm², and medical professionals use mmHg. Each unit provides convenient numbers for typical pressures in that field - tire pressure in bar gives numbers around 2, while in pascals it would be 200,000.
How do I convert tire pressure between psi and bar?
1 bar = 14.504 psi, so divide psi by 14.5 to get bar, or multiply bar by 14.5 to get psi. For example, 30 psi ÷ 14.5 = 2.07 bar. Many European cars recommend pressures around 2.2-2.5 bar, which equals 32-36 psi. Some regions also use kgf/cm²: 1 kgf/cm² ≈ 14.2 psi ≈ 0.98 bar.
What does mmHg mean in blood pressure?
mmHg (millimeters of mercury) measures how high mercury would rise in a column under that pressure. Normal blood pressure around 120/80 mmHg means the pressure could support mercury columns 120mm and 80mm high. This unit persists from early pressure measurement devices that used mercury columns. 1 mmHg = 133.3 pascals = 0.0193 psi.
What's standard atmospheric pressure?
Standard atmospheric pressure at sea level is defined as 101,325 pascals = 1013.25 mbar = 1013.25 hPa = 1.01325 bar = 14.696 psi = 29.92 inHg = 760 mmHg = 760 torr = 1.033 kgf/cm². This represents average pressure at sea level and is used as a reference for many measurements.
How does altitude affect pressure?
Atmospheric pressure decreases with altitude. At 5,000 feet (1,524m), pressure is about 83% of sea level. At 10,000 feet (3,048m), it's about 69%. At commercial aircraft cruising altitude (35,000 feet), it's only about 24% of sea level pressure. This is why aircraft cabins are pressurized to simulate lower altitudes for passenger comfort.
What's the difference between kPa and PSI in everyday use?
kPa (kilopascals) is metric, PSI (pounds per square inch) is imperial. For reference: tire pressure is typically 200-250 kPa (30-36 PSI), home water pressure is around 275-415 kPa (40-60 PSI), and espresso machines operate around 900 kPa (130 PSI). To convert: 1 PSI = 6.895 kPa, 1 kPa = 0.145 PSI.
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