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