Is there a difference between Bar and PSI (Bar vs PSI)?

Generally, pressure is measured in Bar and PSI- PSI, an abbreviation for pound per square inch. Pressure measurement is an essential part of various disciplines such as engineering, chemistry, and physics.

The main difference between Bar and PSI is that the latter measures pressure as a one-pound force applied on an area of one square inch, while the former measures pressure as a force applied perpendicularly on a unit area of a surface.

It’s important to understand the difference between these two units for easy calculation, measurement, and conversion.

In a moment, we will be discussing more on the differences between Bar and PSI.

## What Is Bar?

Bar is a metric unit of pressure that is not part of the International System of Units.

The Bar is also known as “Barometric pressure”. It’s defined as 100,000 pascal (100 kPa) and it represents the load exerted at right angles to one unit volume of a surface to represent pressure.

A pressure of one bar is a bit less than the current average atmospheric pressure at sea level- which is approximately 1.013 bar. Based on the barometric formula, one Bar is approximately the atmospheric pressure at an altitude of 364.174 feet (111 metres) at 15 degrees Celsius (59 degrees Fahrenheit).

Also Read: **Pint vs Quart: Difference and Comparison**

## What Is PSI?

PSI is a unit of measurement of pressure, an imperial and U.S. customary unit of pressure based on the avoirdupois units. PSI is a unit of measurement of pressure that results when a force of one pound-force is applied to a one-square-inch area.

Also, PSI is a unit of measurement that is used to measure pressure or stress. Mathematically, one PSI is approximately 6,985 pascals (N/m^{2 }).

## Bar vs PSI: Current Use

The Bar is a metric unit of pressure that is not part of the International System of Units (S.I.).

However, the International Bureau of Weights and Measures recognizes the Bar and they specified it as a unit that authors can use for measurement and calculation.

Generally, millibars (mb) are often used to reference atmospheric air pressure- where the current average atmospheric pressure is approximately 1.013 bar or 1013.25 Milibars.

Millibar is commonly used by meteorologists and weather reports. It’s a unit that is more preferred, as working in pascals is likely to result in larger values.

### PSI: Current Use

PSI is a unit of measurement of pressure, an imperial and U.S. customary unit of pressure based on the avoirdupois units.

As a unit of measurement, PSI is widely used to measure various pressures like scuba tank pressure, natural gas pipeline pressure, and tire pressure. The PSI is an imperial and U.S. customary unit of pressure that is often used in everyday contexts.

Also Read: **TSP vs TBSP: Difference and Comparison**

## Bar vs PSI: Difference between Bar and PSI

Pressure is measured in both Bar and PSI. Although these two units of measurement are commonly used to measure pressure, there is a difference between Bar and PSI.

The main difference between Bar and PSI is that the latter measures pressure as a one-pound force applied on an area of one square inch, while the former measures pressure as a force applied perpendicularly on a unit area of a surface.

While PSI (pound-force per square inch) specifically measures pressure or stress, Bar is a unit that only measures pressure. When you consider the relationship between these two units of pressure, one bar equals 14.50 PSI, whereas one PSI equals 0.068 bars.

This is one of the main differences between Bar and PSI.

Bar and PSI (pound-force per square inch) are units commonly used to measure pressure. PSI is a unit of measurement of pressure, an imperial and U.S. customary unit of pressure based on the avoirdupois units.

Bar is a unit of measurement of pressure used in the metric system.

## Bar vs PSI: History/ Origin

### PSI

PSI (pound-force per square inch) is a unit of measurement that originated in the imperial and US customary systems of units. It’s a unit of pressure based on the avoirdupois system- a system that was standardized in 1959 and it generally uses weights in terms of the avoirdupois pound.

It’s believed that the system was introduced in Britain during the 14^{th} century. It was the standard system of measurement used in the international wood trade.

### Bar

Bar is a word that has its origin in the ancient Greek- *baros, *a Greek word which means weight. It’s a unit of measurement that was introduced by Norwegian meteorologist Vilhelm Bjerknes.

The official symbol of this unit is “bar”. However, the earlier symbol “b” is currently deprecated and also conflicts with the use of b that denotes the unit barn.

Additionally, the word bar was commonly used for a unit of weight between 1793 and 1795.

Also Read: **Meter vs Yard: Difference and Comparison**

## Bar vs PSI: Comparison Chart

Bar | PSI |

The Bar is defined as 100,000 pascal (100 kPa) and it represents the load exerted at right angles to one unit volume of a surface to represent pressure. | PSI is a unit of measurement of pressure that results when a force of one pound force is applied to a one-square- inch-area. |

Bar is generally used to measure gas and liquid pressure. | PSI is generally used for measuring tire pressure |

The Bar unit is metric | The PSI is the imperial |

1 Bar equals 14.50 PSI | 1 PSI equals 0.068 Bar |

Can be easily converted to kilopascal and millibars | Cannot be easily converted to kilopascal and millibars |

## Bar vs PSI: How to Convert Bar to PSI

Since 1 bar equals 14.503773773 PSI, we only need to multiply one Bar by 14.503773773.

For example, to convert 12 Bar to PSI, we simply multiply 12 by 14.503773773.

So its 12 x 14.503773773 = 174.04528528.

### How to convert PSI to Bar

Since 1 PSI equals 0.0689475729 Bar, we convert it to bar by multiplying the number of PSI by 0.0689475729. For example, to convert 18 PSI to bar, we simply multiply 18 by 0.0689475729.

So it’s 18 x 0.0689475729 = 1.2410563122 bar.

## Frequently Asked Questions

Below are frequently asked questions on the difference between bar vs PSI.

### What is the Bar?

The Bar is defined as 100,000 pascal (100 kPa) and it represents the load exerted at right angles to one unit volume of a surface to represent pressure.

Also Read: **Volume vs Capacity: Difference and Comparison**

### What is PSI?

PSI is a unit of measurement of pressure that results when a force of one pound-force is applied to a one-square-inch area.

### How can I convert PSI to Bar?

Since 1 PSI equals 0.0689475729 Bar, we convert it to bar by multiplying the number of PSI by 0.0689475729. For example, to convert 18 PSI to bar, we simply multiply 18 by 0.0689475729.

So it’s 18 x 0.0689475729 = 1.2410563122 bar.

### How can I convert Bar to PSI?

Since 1 bar equals 14.503773773 PSI, we only need to multiply one Bar by 14.503773773.

For example, to convert 12 Bar to PSI, we simply multiply 12 by 14.503773773.

So its 12 x 14.503773773 = 174.04528528.

## Conclusion

While PSI (pound-force per square inch) specifically measures pressure or stress, Bar is a unit that only measures pressure.

PSI is a unit of pressure based on the avoirdupois system- a system that was standardized in 1959 and it generally uses weights in terms of the avoirdupois pound.

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## References

- Differencebetween: Difference Between Psi and Bar
- GeeksforGeeks: Difference Between PSI and BAR
- Unitconverters.net: Convert bar to psi

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