Standard atmospheric pressure or "the standard atmosphere" (1 atm) is defined as 101.325 kilopascals (kPa) or 760 mmHg. This definition is used for pneumatic fluid power (ISO R554), and in the aerospace (ISO 2533) and petroleum (ISO 5024) industries.
In 1985, IUPAC recommended that standard atmospheric pressure should be 100 000 Pa = 1 bar = 750 Torr. The same definition is used in the compressor and the pneumatic tool industries (ISO 2787).  (see also Standard temperature and pressure)
This can also be stated as:
29 117/127 inches of mercury ˜ 29.92 inHg
1013.25 millibars (mbar, also mb) or hectopascals (hPa)
14.696 psia or 0 psig (pounds-force per square inch, absolute or gauge) (lbf/in²)
2116.2 pounds-force per square foot (lbf/ft²)
1 6517/196133 technical atmospheres (at) ˜ 1.03322745 at
This "standard pressure" is a purely arbitrary representative value for pressure at sea level, and real atmospheric pressures vary from place to place and moment to moment everywhere in the world.