Convert between pressure units for weather, science, and engineering. Professional tool for meteorology, vacuum systems, and industrial applications.
SI unit of pressure. 1 Pa = 1 N/m². Very small unit, often used with prefixes (kPa, MPa).
Metric pressure unit. 1 bar ≈ atmospheric pressure. Common in meteorology and engineering.
Standard atmospheric pressure at sea level. 1 atm = 101.325 kPa. Reference pressure.
Pounds per square inch. Common in US for tire pressure, hydraulics, and industrial applications.
1/760 of atmosphere. Used in vacuum technology and scientific applications. 1 Torr ≈ 1 mmHg.
Traditional pressure unit. Used in blood pressure measurement and vacuum applications.
| Unit | Pascal (Pa) | Bar | atm | PSI | mmHg | Application |
|---|---|---|---|---|---|---|
| 1 Pascal | 1 | 10⁻⁵ | 9.87×10⁻⁶ | 1.45×10⁻⁴ | 7.5×10⁻³ | SI base unit |
| 1 kPa | 1,000 | 0.01 | 9.87×10⁻³ | 0.145 | 7.5 | Weather systems |
| 1 Bar | 100,000 | 1 | 0.987 | 14.5 | 750 | Industrial standard |
| 1 atm | 101,325 | 1.013 | 1 | 14.7 | 760 | Sea level pressure |
| 1 PSI | 6,895 | 0.069 | 0.068 | 1 | 51.7 | US industrial |
| 1 mmHg | 133.3 | 1.33×10⁻³ | 1.32×10⁻³ | 0.019 | 1 | Medical/vacuum |
Fundamental definition of pressure as force per unit area.
Pressure in fluids due to depth and gravity.
Relationship between different pressure references.
Pressure in ideal gases. P=pressure, V=volume, n=moles, R=gas constant, T=temperature.
Atmospheric pressure variation with altitude.
Pressure in moving fluids (constant density).
| Standard | Value (Pa) | Value (other units) | Application |
|---|---|---|---|
| Standard Atmosphere | 101,325 | 1 atm = 760 mmHg = 1.01325 bar | Reference pressure |
| Technical Atmosphere | 98,066.5 | 1 at = 1 kgf/cm² | Engineering reference |
| Mercury Column (0°C) | 133,322 | 1 mmHg = 1 Torr | Vacuum measurement |
| Water Column (4°C) | 9,806.65 | 1 cmH₂O | Low pressure measurement |
| Perfect Vacuum | 0 | 0 absolute pressure | Vacuum reference |
| Tire Pressure (typical) | 220,000 | 32 PSI = 2.2 bar | Automotive |
10 m underwater: 2 atm (1 atm + 1 atm water)
100 m (scuba limit): 11 atm
1000 m (deep sea): 101 atm
Mariana Trench (11 km): 1100 atm
1500 m (Denver): 850 mbar (0.84 atm)
3000 m (high mountains): 690 mbar (0.68 atm)
5500 m (Everest base camp): 500 mbar (0.5 atm)
8848 m (Everest summit): 337 mbar (0.33 atm)
Aircraft cabin: 750-800 mbar (cabin pressure)
Space suit: 200-300 mbar (pure oxygen)
Mars atmosphere: 6 mbar (0.6% of Earth)
Venus surface: 9200 kPa (92 atm)