PressureConverter
Instantly convert pressure units including Pascal, Kilopascal, and more.
About Pressure Units
Pressure is force applied perpendicular to a surface per unit area. The SI unit, the Pascal (Pa), equals one Newton per square meter — a small quantity, so kilopascals (kPa) and megapascals (MPa) are common in engineering. Standard atmospheric pressure at sea level is 101,325 Pa (1 atm), a useful baseline for weather and aeronautics. The bar (100,000 Pa) dominates in meteorology and industrial gauges. PSI (pounds per square inch) is standard in the United States for tire inflation, plumbing, and gas cylinders. Blood pressure is still measured in millimeters of mercury (mmHg), a legacy of mercury manometers.
Evangelista Torricelli's invention of the mercury barometer in 1643 gave scientists their first quantitative tool for measuring atmospheric pressure. Blaise Pascal immediately grasped the significance: he had a barometer carried up the Puy-de-Dôme mountain in 1648 and confirmed that air pressure decreases with altitude — one of the earliest experimental verifications of a physical hypothesis. The steam engines of the Industrial Revolution (18th–19th centuries) created urgent practical demand for reliable pressure measurement; boiler explosions due to unchecked pressure were a major cause of industrial accidents. The SI Pascal was adopted in 1971, named in honor of Pascal's contributions.
Pressure conversion is essential across multiple disciplines. A motorist checks tire pressure in psi in the US or bar in Europe. A weather forecaster reports atmospheric pressure in millibars (1 mbar = 100 Pa = 0.001 bar) or hectopascals (hPa, numerically identical to mbar). A physician reads blood pressure as mmHg: 120/80 mmHg equals about 16.0/10.7 kPa. An industrial engineer designing hydraulic systems in Germany works in bar, while their American counterpart uses psi — and must convert carefully for any joint specification. Deep-sea research vessels monitor hull stress in megapascals.
Common Pressure Conversions
| From | To |
|---|---|
| 1 atm | 101,325 Pa — 1.01325 bar — 14.696 psi |
| 1 bar | 100,000 Pa — 0.9869 atm — 14.504 psi |
| 1 psi | 6,894.76 Pa — 0.06895 bar |
| 1 kPa | 1,000 Pa — 0.145 psi |
| Tyre pressure (typical) | 30–35 psi — 2.07–2.41 bar — 207–241 kPa |
| Blood pressure (systolic) | ~120 mmHg ≈ 16 kPa |
| 1 mmHg | 133.322 Pa — 0.0193 psi |
| 1 MPa | 1,000 kPa — 145.04 psi |
| 1 mbar (hPa) | 100 Pa — 0.0145 psi |
| Sea-level pressure | 1,013.25 mbar — 101,325 Pa |
| 10 m seawater depth | +1 atm extra ≈ 14.7 psi ≈ 1 bar |
| 1 atm | 760 mmHg — 101.325 kPa |
| 60 psi | 413.7 kPa — 4.137 bar |
| 2.5 bar | 250 kPa — 36.26 psi |
| 1 kPa | 7.5006 mmHg — 0.00987 atm |
Frequently Asked Questions
101,325 Pa = 1 atm = 1.01325 bar = 14.696 psi. This is the defined average pressure at sea level on a standard day and serves as the reference point for many pressure-related calculations.
Most passenger cars recommend 2.0–2.5 bar (29–36 psi). Always check the label inside your driver's door, the owner's manual, or the tyre sidewall — the correct pressure depends on the vehicle and load.
Exactly 100,000 Pa (100 kPa) equal one bar. The bar is not an SI unit but is accepted for use with SI.
Absolute pressure includes atmospheric pressure; gauge pressure is measured relative to the atmosphere. A car tyre at '32 psi gauge' is actually at about 46.7 psi absolute (32 + 14.7). Gauge pressure is more practical for everyday tools; absolute pressure is needed for gas law calculations.
Air pressure decreases roughly 1.2 kPa (about 0.17 psi) per 100 meters of altitude at sea level. At 3,000 m (about 10,000 ft), pressure is approximately 70 kPa (0.70 atm). Aircraft cabins are pressurized to an equivalent altitude of about 2,000–2,400 m to keep passengers comfortable.
The average surface pressure on Mars is about 600–700 Pa — less than 1% of Earth's 101,325 Pa. This is why Mars's thin atmosphere cannot support liquid water or unprotected human life.
Multiply bar by 14.504. For example, 2 bar × 14.504 = 29 psi. Reverse: multiply psi by 0.0689 to get bar. A quick approximation: 1 bar ≈ 14.5 psi.
The standard healthy blood pressure for an adult is below 120/80 mmHg (systolic/diastolic). That is approximately 16.0/10.7 kPa or 1.74/1.16 psi. High blood pressure (hypertension) is generally defined as ≥ 130/80 mmHg.