Kilopascals to millimeters of water converter above calculates how many millimeters of water are in 'X' kilopascals (where 'X' is the number of kilopascals to convert to millimeters of water). In order to convert a value from kilopascals to millimeters of water (from kPa to mmH2O) just type the number of kPa to be converted to mmH2O and then click on the 'convert' button.