Kilopascals to millimeters of mercury conversion calculator shown above calculates how many millimeters of mercury are in 'X' kilopascals (where 'X' is the number of kilopascals to convert to millimeters of mercury). In order to convert a value from kilopascals to millimeters of mercury (from kPa to mmHg) simply type the number of kPa to be converted to mmHg and then click on the 'convert' button.