The kilopascals -- abbreviated as kPa -- is a common metric unit of pressure. Psi stands for pounds per square inch, a unit of pressure in the United States. Pressure measures the perpendicular force against an object, such as the air pressing against the wall of a tire. If a pressure requirement is reported in kPa, but your pump only measures in psi, you must convert to make sure that you have the proper pressure.

Multiply the number of kPa by 0.145 to find the number of psi. For example, if you had 120 kPa, multiply 120 by 0.145 to get about 17.4 psi.

Divide the number of kPa by 6.895 to convert to psi. For example, if you had 120 kPa, divide 120 by 6.895 to get about 17.4 psi.

Use an online conversion calculator to verify your results, or to obtain more precise measurements.