Pressure conversion units

In the International System of unit the units of measure of the pressure is Newton to the square meter (N/m2) defined Pascal (Pa). For convention the atmosphere is defined as the pressure to sea level from one high mercury column 760 millimeter (1 atm ~ 10e+5 Pa).

Pascal (Pa) is the metric SI unit of pressure and the standard pressure unit in the MKS metric system, equal to 1 Newton per square meter. In English terms, 1 Pascal is only 0.000145 pounds per square inch (0.020885434 lbf/ft2 or 0.00750 mmHg). Thus pressure is more commonly measured in kilopascals (kPa), with 1 kPa = 0.145 lbf/in2. For automatic pressure conversion:
http://www.coleparmer.com/Techinfo/converters/commpressure.asp