Standard Atmosphere

Equivalents to 1 atmosphere are as follows:
76 centimeters (760 mm) of mercury
29.921 inches of mercury
10.3322 meters of water
406.782 inches of water
33.899 feet of water
14.696 pounds-force per square inch
2,116.2 pounds-force per square foot
1.033 kilograms-force per square centimeter
101.325 kilopascal
The unit “1 Standard Atmosphere” is defined as the pressure equivalent to that exerted by a 760 mm column of mercury at 0°C (32°F), at sea level, and at standard gravity (32.174 ft/sec2). Atmospheric pressure is the weight of a column of air per area unit as measured from the top of the atmosphere to the reference point being measured. Atmospheric pressure decreases as altitude increases.