What is pascal?
The pascal is the SI base unit of pressure, equal to one newton per square metre. It is used in meteorology, fluid dynamics, materials science, and all scientific pressure measurements.
Real-world uses
The pascal is the SI unit of pressure used in engineering stress analysis, materials science, and acoustics (sound pressure levels). Concrete and steel specifications list compressive strength in megapascals (MPa). Atmospheric pressure is about 101,325 Pa.
History
Named after Blaise Pascal, the French mathematician and physicist who conducted pioneering experiments on fluid pressure and vacuum in the 1640s. The pascal was adopted as the SI unit of pressure in 1971 at the 14th General Conference on Weights and Measures.
Common mistakes
Using pascals directly for everyday pressure is impractical since one pascal is a very small pressure (about the weight of a dollar bill spread over a desk). Most practical applications use kPa, hPa, or MPa instead.
What is bar?
A bar is a pressure unit approximately equal to standard atmospheric pressure, or 100,000 pascals. It is widely used in meteorology, hydraulics, diving equipment, and industrial pressure gauges.
Real-world uses
Bars are widely used in European tyre pressure specifications, compressed gas cylinder ratings, scuba diving depth gauges, and industrial process controls. Espresso machines operate at 9–15 bar. Atmospheric pressure is approximately 1.013 bar.
History
The bar was introduced by Norwegian meteorologist Vilhelm Bjerknes in 1909, derived from the Greek word "baros" meaning weight. Though not an SI unit, it is widely accepted in industry and was retained in the EU Directive on units of measurement.
Common mistakes
Confusing bar with atm—they are close (1 atm ≈ 1.01325 bar) but not identical. Also, gauge pressure (barg) versus absolute pressure (bara) is often mixed up; gauge pressure reads zero at atmospheric pressure.
When is this conversion used?
Tyre pressure gauges, HVAC systems, and industrial equipment may use different pressure units depending on the manufacturer and region. Converting between psi, bar, and kPa is common in automotive and engineering work.
Worked examples
1 pascal = 0.00001 bar
1 bar = 100,000 pascal
How to convert pascal to bar
To convert pascal to bar, multiply the value by 0.00001.
To convert bar back to pascal, multiply by 100,000.
Measurement standards
The pascal (Pa) is the SI derived unit of pressure, defined as one newton per square metre. The World Meteorological Organization mandates the hectopascal (hPa) for atmospheric pressure reporting in aviation and weather services.
Did you know?
The pressure at the bottom of the Mariana Trench, nearly 11 km deep, exceeds 1,086 bar — over a thousand times atmospheric pressure. At this depth, water is compressed by about 5%, making it measurably denser than at the surface.
Quick reference: pascal to bar
| pascal | bar |
|---|---|
| 0.1 | 0.000001 |
| 0.5 | 0.000005 |
| 1 | 0.00001 |
| 2 | 0.00002 |
| 5 | 0.00005 |
| 10 | 0.0001 |
| 25 | 0.00025 |
| 50 | 0.0005 |
| 100 | 0.001 |
| 250 | 0.0025 |
| 500 | 0.005 |
| 1,000 | 0.01 |
Common values
| pascal | bar | |
|---|---|---|
| Car tyre | 220,000 pascal | 2.2 bar |
| Standard atmosphere | 101,325 pascal | 1.01325 bar |
| Blood pressure (systolic) | 16,000 pascal | 0.16 bar |
| Deep-sea submersible | 110,000,000 pascal | 1,100 bar |
| Bicycle tyre | 620,000 pascal | 6.2 bar |