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