# ››Convert pound/square inch [gauge] to pound/square inch [absolute]

 psig psia

The above form works if you are measuring differential pressure, such as the difference in psi between two points.

If you are measuring relative to vacuum and want to resolve the pressure relative to the atmosphere, then you should use the form below.

Note that psig can measure differential pressure in some applications and absolute pressure in others, so you need to know which one fits your calculation.

psig (relative to atmosphere)
psia (relative to vacuum)

How many psig in 1 psia? The answer is 1.
We assume you are converting between pound/square inch [gauge] and pound/square inch [absolute].
You can view more details on each measurement unit:
psig or psia
The SI derived unit for pressure is the pascal.
1 pascal is equal to 0.00014503773800722 psig, or 0.00014503773800722 psia.
Note that rounding errors may occur, so always check the results.
Use this page to learn how to convert between pounds/square inch and pounds/square inch.
Type in your own numbers in the form to convert the units!

# ››Want other units?

You can do the reverse unit conversion from psia to psig, or enter any two units below:

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# ››Definition: Pound/square inch

Psig (pound-force per square inch gauge) is a unit of pressure relative to the surrounding atmosphere. By contrast, psia measures pressure relative to a vacuum (such as that in space). At sea level, Earth's atmosphere actually exerts a pressure of 14.7 psi. Humans do not feel this pressure because internal pressure of liquid in their bodies matches the external pressure. If a pressure gauge is calibrated to read zero in space, then at sea level on Earth it would read 14.7 psi. Thus a reading of 30 psig on a tire gauge represents an absolute pressure of 44.7 psi.

# ››Definition: Pound/square inch

Pounds per square inch absolute (psia) is used to make it clear that the pressure is relative to a vacuum rather than the ambient atmospheric pressure. Since atmospheric pressure at sea level is around 14.7 psi, this will be added to any pressure reading made in air at sea level.

# ››Metric conversions and more

ConvertUnits.com provides an online conversion calculator for all types of measurement units. You can find metric conversion tables for SI units, as well as English units, currency, and other data. Type in unit symbols, abbreviations, or full names for units of length, area, mass, pressure, and other types. Examples include mm, inch, 100 kg, US fluid ounce, 6'3", 10 stone 4, cubic cm, metres squared, grams, moles, feet per second, and many more!