Difference Between Bar And Barg

The major difference between bar and barg is that bar means absolute pressure, and barg means gauge pressure.

What is pressure? Pressure is defined as the force applied on any given surface. The three types of pressure are Absolute, Gauge, and Differential pressure.

Absolute pressure is a unit measurement taken against a vacuum on an absolute scale. Gauge power is measured against the air pressure. On the other hand, differential pressure is the pressure of an object at two points.

What is Bar?

The unit measurement bar helps measure any object’s absolute pressure. The metric unit of one bar is equal to 100,000 Pa. Here are some of the units derived from bars:

  • Millibar
  • Centibar
  • Megabar
  • Kilobar
  • Decibar

Moreover, one bar equals 0.987 atm, 750.06 mmHg, and 14.50 psi (absolute pressure). The standard pressure at sea level is 1013.25 millibar.

Did you know that most engineers use a bar rather than Pascal because the Pascal unit system involves calculations with large numbers?

What is Barg?

Barg is used to measure the gauge pressure. Gauge pressure is the difference between absolute pressure and atmospheric pressure.

Difference Between Bar And Barg

The main difference between “bar” and “barg” is how they measure pressure. “Bar” measures absolute pressure, while “barg” measures gauge pressure.

When we talk about pressure, there’s also something called atmospheric pressure, which is the pressure exerted by the air around us. To get absolute pressure, we add gauge pressure to atmospheric pressure. But for gauge pressure, we subtract atmospheric pressure from absolute pressure.

For instance, if we’re measuring pressure in a vacuum, we’d use the unit “bar.” But if we’re measuring pressure with the atmosphere around us, we’d use “barg.”

Comparison Table For Bar Vs. Barg

head-to-head comparison table for BarG (Gauge Pressure) and Bar (Absolute Pressure) based on the provided content:

Feature BarG (Gauge Pressure) Bar (Absolute Pressure)
Definition The bar helps to measure absolute pressure. Brag is the unit of measurement used to measure gauge pressure.
Relationship Measure any pressure by gauge pressure added to the atmospheric pressure. The difference between and the atmospheric pressure.
Example Finding out the pressure in the vacuum. Measuring the pressure in an environment that has atmospheric pressure.
Calculation Gauge pressure + Atmospheric pressure Absolute pressure = Gauge pressure + 1 atmosphere
Usefulness Useful for practical measurements More technically correct but less practical
Typical Reference Compressor pressure, system pressure Standard atmosphere, theoretical vacuum
Industry Application Commonly used in pneumatic systems Less commonly used due to its theoretical nature
Conversion Add atmospheric pressure to gauge pressure Subtract atmospheric pressure from absolute pressure


Pressure is the force applied on the surface perpendicularly. There are three types of pressure: differential, Gauge, and Absolute. The bar measurement measures absolute pressure, while the barg measures gauge pressure.

We hope that this article helps you gain a better understanding of the topic.

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