Metallica was the first album in the SoundScan era to surpass 16 million sales in the United States.
The album’s commercial achievement reflects unusually persistent demand rather than a brief release-week peak. Nielsen SoundScan tracking began in 1991, the same year Metallica was released, and the record continued selling steadily across physical formats and later reissues.
By 2016, the album had sold 16.4 million copies in the United States, including 5.8 million on cassette. It later received a 2× Diamond certification from the Recording Industry Association of America for shipping 20 million copies in the country.
This record is commonly confused with the album’s worldwide sales, which exceeded 30 million copies. The 16-million figure refers specifically to United States sales tracked during the SoundScan era, while the worldwide total covers a much larger international market.