Conversions of pressure units : Everything you need to know

The commonly used units of pressure are the pascal (Pa), the standard atmosphere (atm), the bar, the millimetre of mercury (mmHg) and the psi. The pascal is the international and legal unit of pressure, corresponding to 1 newton per square metre (1 Pa = 1 N/m²). Other pressure units are converted from the pascal. For example, 1 bar equals 100,000 Pa and 1 atm equals 101,325 Pa. There are also other pressure units, such as millimetres of mercury, centimetres of water and psi, which are used in specific fields.

Knowing the equivalence between these units makes it easy to convert pressure from one unit to another.

Conversions of pressure units


An Introduction to Pressure

Pressure is a fundamental physical quantity

Pressure is a fundamental physical quantity used to measure the force exerted on a given surface. It plays a crucial role in various fields such as meteorology, industry and physics. Understanding what is a pressure transmitter, the units of pressure and how to convert them is essential for correctly interpreting pressure measurements and assessments.

Pressure is defined as the quotient of a force (F) over the area of the surface (S) to which it is applied: p = F/S. There are different units of pressure used around the world, each with its own specific field of application and equivalences.

A detailed explanation of Pressure units

In this article, we'll give you a detailed explanation of the most commonly used pressure units and show you how to convert between them. Here's all you need to know:


A detailed explanation of pressure units and their conversion

The International Pressure Unit: The Pascal (Pa)

The International Pressure Unit: The Pascal (Pa)

The pascal (Pa) is the unit of pressure in the International System of Units (SI). It is defined as the pressure exerted by a force of 1 newton on a surface of 1 square meter.

The pascal is the reference unit for all other pressure units.


Commonly used pressure units

Commonly used pressure units

  • Atmosphere (atm) Atmosphere is a unit of pressure used to measure atmospheric pressure. One atmosphere is equivalent to the pressure exerted by a 760 mm column of mercury at 0°C. 1 atm = 101,325 Pa.

  • The bar: The bar is a unit of pressure commonly used to measure the pressure of tyres, oxygen and acetylene cylinders, as well as in scuba diving applications. One bar is approximately equal to atmospheric pressure. 1 bar = 100,000 Pa.
  • The millimeter of mercury (mmHg): The millimeter of mercury, also known as the torr, is a unit of pressure historically used in physics. 760 mmHg corresponds to one atmosphere at 0°C. 1 mmHg = 133.322368 Pa at 0°C.
  • The psi (pound per square inch): The psi is a unit of pressure widely used to measure tyre pressure. 1 psi is equivalent to approximately 6894.76 Pa.


 Pressure unit conversion table

The table below provides a list of the main pressure units with their respective conversion factors to Pascal.

Pressure unitsEquivalence in Pascal
Technical atmosphere98066.5 Pa
Standard atmosphere101325 Pa
Centimeter of water98.0638 Pa
Centimeter of water at 4°C98.0638 Pa
Centimeter of water at 60°F98.0638 Pa
Centimeter of water at 68°F98.0638 Pa
Centimeter of Mercury1333.22 Pa
Feet of water column2988.98 Pa
Feet of water column at 4 °C2988.98 Pa
Feet of water column at 60°F2986.116 Pa
Feet of water column at 68°F2986.116 Pa
Kilogram-force per square centimeter98066.5 Pa
Hectopascal100 Pa
Inch of water column248.082 Pa
Inch of water column at 4 °C248.082 Pa
Inch of water column at 60°F248.843 Pa
Inch of water column at 68°F248.843 Pa
Inch of Mercury3386.389 Pa
Inches of water column249.082 Pa
Torr133.3224 Pa
Unit1 Pa
Bar100000 Pa
Kilogram-force per square meter9.80665 Pa
Kilonewton per square metre1000 Pa
Millibar100 Pa
Meter of water column9806.38 Pa
Meter of Mercury133322 Pa
Millimeter of water column9.80638 Pa
Millimeter of water column at 4°C9.80638 Pa
Millimeter of water column at 60°F9.80638 Pa
Millimeter of water column at 68°F9.80638 Pa
Millimeter of Mercury133.3224 Pa
Millimeter of Mercury at 0 °C133.3224 Pa
Megapascal1000000 Pa
Ounces force per square inch430.92233 Pa
Pascal1 Pa
Pounds per square inch6894.757 Pa

Frequently asked questions (FAQ)

Q1: What are the pressure units?

what-are-pressure-units

A1: The commonly used units of pressure measurement are the pascal (Pa), the standard atmosphere (atm), the bar, the millimetre of mercury (mmHg), and the psi. Other units are also used, including the pound per square inch (lbf/in²), kilogram-force per square metre (kgf/m²), kilonewton per square metre (kN/m²), and millibar.

 

Q2: How do you convert pressure into bar?

A2: To convert pressure to bar, divide the pressure value in pascals by 100,000.

Q3: How do you convert bars into kilograms?

A3: To convert bar into kilograms, use the relationship 1 bar = 1 kg/cm².

Q4: How do you convert pressure units?

A4: To convert a pressure value to another unit, use the specific conversion relationship between the two units and multiply the pressure value by the appropriate conversion factor. To convert pressure units, you can use an online converter or apply the appropriate conversion factors.

Q5: What is a pressure unit?

A5: A unit of pressure is a measurement used to quantify the force exerted on a surface.

Q6: What units of pressure are used in the International System (SI)?

A6: In the international system, the basic unit of pressure is the pascal (Pa). There are also multiples of the pascal, such as the hectopascal (hPa), the megapascal (MPa) and the gigapascal (GPa).

Q7: What is the technical atmosphere?

A7: The technical atmosphere (at or ATA) is a unit of pressure equivalent to the kilogram-force per square centimetre (kgf/cm²).

Q8 : Is there a pressure unit converter?

is there a pressure-unit-converterA8: Yes, there are online converters that allow you to convert pressure values between different units. These tools can be useful for making quick and accurate conversions.

Q9: What is a centimetre of water column (cmH2O)?

A9: The centimetre of water column is a unit of pressure that measures the pressure exerted by a column of water 1 centimetre high. It is often used in medical and ventilation applications.

Q10: What is the inch of mercury (inHg)?

A10: The inch of mercury is a unit of pressure which measures the pressure exerted by a column of mercury one inch high. It is often used in the aviation and meteorology industries.

Q 11: What is the difference between absolute pressure and gauge pressure ?

Gauge pressure represents the difference in pressureA11: Absolute pressure measures pressure in relation to an absolute vacuum, whereas relative pressure measures pressure in relation to atmospheric pressure. Gauge pressure is equal to absolute pressure minus atmospheric pressure. The formula for calculating absolute pressure from relative pressure is as follows:


Gauge pressure represents the difference in pressure compared with atmospheric pressure, while absolute pressure is measured in relation to the absolute vacuum, where pressure is zero. By adding atmospheric pressure to gauge pressure, we obtain absolute pressure.

It is important to note that atmospheric pressure varies according to altitude and atmospheric conditions. It is therefore essential to take atmospheric pressure into account when calculating absolute pressure. 


This formula converts a gauge pressure measurement into an absolute pressure measurement by taking into account the zero reference for absolute pressure, which is the absolute vacuum.what-is-the-difference-between-absolute-pressure-and-gauge-pressure

Q12: What pressure units are commonly used in industry?

A12: In industry, pressure units such as bar, psi, kg/cm², MPa and inHg are commonly used to measure pressure in different contexts and applications.

Q13: What is a hectopascal (hPa)?

A13: The hectopascal is a unit of pressure equivalent to 100 pascals. It is often used in meteorology to measure atmospheric pressure.

Q14: What is the symbol for Pascal?

A14: The pascal symbol is Pa, in reference to the French physicist Blaise Pascal.


Become an Expert in Conversions of pressure units

Become an Expert in Conversions of pressure units

We hope this article has provided you with a clear understanding of pressure units and their conversion. Feel free to use online converters to make your conversion calculations easier.
Always remember to consider the appropriate units when interpreting pressure measurements, as this may vary depending on context and application.

Remember to consult the standards and references specific to your area of interest for more detailed information on pressure units and their use.


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