Millimeters of water to millipascals converter on this page calculates how many millipascals are in 'X' millimeters of water (where 'X' is the number of millimeters of water to convert to millipascals). In order to convert a value from millimeters of water to millipascals (from mmH2O to mPa) just type the number of mmH2O to be converted to mPa and then click on the 'convert' button.