According to Billboard, Nielson Music announced the staggering - and record-breaking - amount on Saturday, one week and one day after the album's release.
The superstar's third studio album is responsible for the most sales in one week of a particular record since the Nielson agency started keeping track of point-of-sale album purchases in 1991.
Earlier in the week, Adele thundered by the previous record holder, boy band NSYNC.
That group's album No Strings Attached sold 2.42 million copies in one week back in 2000.
NSYNC member Joey Fatone talked to Billboard about Adele breaking their record - and admitted even he bought her new album.
'I thought this one would be tough to beat,' admitted Joey, 38. 'In all honesty, Adele is the truth - kinda excited a rare talent like hers is in the same breath as our group. I'm a huge fan... I even bought the damn album.'
In another shocking development, Adele has demolished the record for most albums sold in 2015, which was previously held by pop phenom Taylor Swift's 1989, which boasted 1.8 million units sold.
Of course Adele should be used to such levels of success, as her past album 21 spent 24 weeks on top of the Billboard 200, which was the longest ever for a female artist.
That album was the 10th-highest selling album in the history of Nielson.
And Adele just keeps delighting fans.
In a video posted on her Instagram page on Thursday, the 27-year-old star confessed that she had been 'bluffing' about not going on tour.
It will be the first time the British singer has toured in five years, following her 2011 Adele Live series of concerts following the release of her second album 21.