 In the U.S. , Halo 3 sold 3 @.@ 3 million copies in its first 12 days on sale , increasing to 3 @.@ 7 million copies by November 15 , 2007 . Reuters UK estimated that Halo 3 may have sold up to 5 @.@ 2 million copies worldwide in the first two weeks after launch . By November 30 , 2007 , Halo 3 had sold 5 million copies worldwide , and as of that point , was the best @-@ selling video game of 2007 in the U.S. , even though the game is only available on one console . On January 3 , 2008 , Microsoft announced that Halo 3 has sold 8 @.@ 1 million copies . The game drew over a million Xbox Live members to play online in the first 20 hours , making it the biggest day for Xbox Live gaming in history . The game returned to the top 20 sales charts more than a year after its release in February 2009 ; Gamasutra reported that the boost might have been due to the release of Halo Wars . By January 2008 , 8 @.@ 1 million copies had been sold . According to Microsoft , Halo 3 had sold 14 @.@ 5 million copies as of 2012 . 
