Official results released by the electoral commission late on Monday showed Mutharika had built a commanding lead over incumbent Lazarus Chakwera in the September 16 election.
A candidate needs to secure more than 50% of valid votes for an outright win, otherwise there will be a second round of voting.
Political analysts had predicted that Mutharika, 85, who was in power between 2014 and 2020, would mount a strong challenge to Chakwera's re-election bid, as the economy has worsened since the last election.
(Reporting by Frank Phiri; Writing by Alexander Winning; Editing by Bate Felix)