PSIG to PSIA Conversion Calculator

Pressure measurements are a fundamental aspect of various process engineering and instrumentation and control applications. Pressure is typically measured in two main forms: PSIG (pounds per square inch gauge) and PSIA (pounds per square inch absolute). 

This calculator helps you convert PSIG to PSIA accurately.

What is PSIG? 

PSIG(Pounds per Square Inch Gauge) is a measure of pressure relative to the ambient atmospheric pressure. This means that it only considers the pressure in excess of the atmospheric pressure around us. For example, if a tire gauge shows 30 PSIG, it means the pressure inside the tire is 30 PSI above the atmospheric pressure. This type of measurement is commonly used in various applications such as automotive tire pressure, HVAC systems, and other industrial processes where the influence of atmospheric pressure is not a primary concern.

Key Information about PSIG:

• It is a gauge pressure, meaning it measures the difference between the internal pressure and the surrounding atmospheric pressure.
• It does not account for the atmospheric pressure itself.
• Widely used in day-to-day applications where the difference from atmospheric pressure is more relevant than the absolute pressure.

What is PSIA?

PSIA (Pounds per Square Inch Absolute), on the other hand, measures the total pressure, including the atmospheric pressure. This is crucial in scientific and engineering calculations where absolute pressure values are necessary for accuracy. 

The atmospheric pressure at sea level is typically 14.7 PSI. Thus, PSIA is always higher than PSIG by the amount of atmospheric pressure. For instance, if you measure a vacuum in PSIA, it would show zero PSIA in a perfect vacuum (no atmospheric pressure), while a PSIG measurement would read -14.7 PSI under the same conditions.

Key Information about PSIA:

• It is an absolute pressure, measuring the total pressure including the atmospheric pressure.
• Important in scientific and technical applications where precise pressure measurements are critical.
• Commonly used in calculations involving gas laws, thermodynamics, and fluid dynamics where the absolute pressure impacts the behavior of gasses and fluids.

What is Atmospheric Pressure ?

Atmospheric pressure is the force exerted by the weight of the air above a given point on Earth’s surface. It is a crucial concept in both meteorology and various engineering applications.

Atmospheric pressure is the pressure exerted by the Earth’s atmosphere at any given point due to the weight of the air column above that point.

At sea level, the standard atmospheric pressure is approximately 101.3 kilopascals (kPa), 1 atmosphere (atm), or 14.7 pounds per square inch (PSI). This is often referred to as “standard atmospheric pressure.”

By understanding the distinction between PSIG and PSIA, you can ensure accurate pressure measurements and conversions, especially in contexts where the absolute pressure is critical for correct results.

Conversion Calculator: PSIG to PSIA 

The below calculator used to convert the PSIG(Pounds per Square Inch Gauge) to PSIA (Pounds per Square Inch Absolute)

How to convert PSIG to PSIA?

Input: PSIG value (e.g., 50)

Output: PSIA value

Enter the PSIG value.

Click on the calculate button and the calculator adds the atmospheric pressure (14.7 PSI) to the entered PSIG value.

The resulting value is the pressure in PSIA.

PSIG to PSIA Conversion Formula

To convert PSIG to PSIA, you need to account for the atmospheric pressure. At sea level, the typical atmospheric pressure is roughly 14.7 pounds per square inch (PSI).  The formula for conversion is:

PSIA=PSIG + Atmospheric Pressure (14.7 PSI)

Example PSIG to PSIA Conversion Calculation

To help you understand the conversion procedure, let’s look at an example:

Given data:

• PSIG = 50 PSI
• Atmospheric Pressure = 14.7 PSI

Calculation:

PSIA=PSIG+Atmospheric Pressure

PSIA = 50+14.7

PSIA = 64.7

Therefore, 50 PSIG is equal to 64.7 PSIA.

Here you can refer more Online Instrumentation Calculators Collections

Frequently Asked Questions (FAQ) About PSIG and PSIA

What is the full form of PSIG?

PSIG stands for Pounds per Square Inch Gauge. It measures pressure relative to atmospheric pressure, meaning it tells you the pressure above or below the atmospheric level.

What is the difference between PSIG and PSIA?

• PSIG (Pounds per Square Inch Gauge) measures pressure relative to atmospheric pressure. It is used to gauge how much pressure is exerted above or below the atmosphere at a specific location.
• PSIA (Pounds per Square Inch Absolute) measures pressure relative to a vacuum (absolute zero pressure). At sea level, 1 atmosphere of pressure is approximately 14.7 PSIA.

Difference Between PSI, PSIA, and PSIG

How do you convert PSIG to PSIA?

To convert PSIG to PSIA, simply add atmospheric pressure (14.7 at sea level) to the PSIG value.
Formula: PSIA = PSIG + 14.7

How do you convert PSIA to PSIG?

To convert PSIA to PSIG, subtract atmospheric pressure (14.7 at sea level) from the PSIA value.
Formula:
PSIG = PSIA – 14.7

What is 14.7 PSIA?

14.7 PSIA is the atmospheric pressure at sea level. It is the standard pressure at Earth’s surface, where 0 PSIG is the same as 14.7 PSIA.

Can you provide a conversion chart for PSIG to PSIA?

What is PSI?

PSI (Pounds per Square Inch) is a general term used to describe pressure. It is often used interchangeably with PSIA unless specified as PSIG, as it does not explicitly indicate whether the pressure is absolute or gauge pressure.

Why is PSIG always lower than PSIA?

PSIG is always lower than PSIA because PSIA includes the atmospheric pressure (14.7 PSIA at sea level), while PSIG is a gauge that only measures the pressure relative to the atmospheric level. For instance, at sea level, 0 PSIG means there is no pressure above or below atmospheric pressure, but the PSIA is 14.7.

Can you give an example of calculating PSIA and PSIG?

1. If you have 50 PSIG:
   • PSIA = PSIG + 14.7
   • PSIA = 50 + 14.7 = 64.7 PSIA
2. If you have 100 PSIA:
   • PSIG = PSIA – 14.7
   • PSIG = 100 – 14.7 = 85.3 PSIG

What is the unit of atmospheric pressure?

The unit for atmospheric pressure is commonly 14.7 PSIA at sea level. This is used in the conversions between PSIG and PSIA.