Pressure is force divided by area, so in the metric system pressure is measured in newtons per square meter, called a pascal (Pa). One pascal is a very small pressure, so usually the kPa, or 1,000 Pa, is used. In the English system, pounds per square inch (psi) is often used. Another unit used is a measurement of the height of mercury in a glass tube that would create a pressure that balances the pressure of the fluid. That unit that used to be called millimeters of mercury is now called the torr. Here is how these units compare: 760 torr = 14.7 psi = 101.3 kPa.