Metallica was the first album in the Nielsen SoundScan era to surpass 16 million US sales.
Nielsen SoundScan began tracking US music purchases in 1991, the same year Metallica was released. The album’s sustained sales eventually made it the best-selling album in the United States since SoundScan tracking began, surpassing releases from artists in pop, rock, and country.
By 2016, reported US sales had reached about 16.4 million copies, including approximately 5.8 million cassettes. The album continued selling steadily long after its initial chart run, helped by recurring catalog interest, touring, and multiple reissues.
This statistic is often confused with worldwide sales. Metallica has sold more than 30 million copies globally, but the SoundScan distinction concerns US sales measured within that tracking era. It also differs from the RIAA certification system, which records shipments rather than the same sales measure.