Hartree to milli-electron volts conversion calculator above calculates how many milli-electron volts are in 'X' Hartree (where 'X' is the number of Hartree to convert to milli-electron volts). In order to convert a value from Hartree to milli-electron volts (from Ha to meV) just type the number of Ha to be converted to meV and then click on the 'convert' button.