Pounds per square inch to centimeters of water conversion calculator above calculates how many centimeters of water are in 'X' pounds per square inch (where 'X' is the number of pounds per square inch to convert to centimeters of water). In order to convert a value from pounds per square inch to centimeters of water (from psi to cmH2O) just type the number of psi to be converted to cmH2O and then click on the 'convert' button.