Metallica became the first album in the Nielsen SoundScan era to pass 16 million U.S. sales.
The record is officially titled Metallica but is commonly called The Black Album. Nielsen SoundScan began tracking U.S. music sales in 1991, the same year the album was released, allowing its long-term performance to be measured across physical formats and later market changes.
By 2016, the album had sold about 16.4 million copies in the United States. It was also described as the best-selling U.S. album of the SoundScan era, surpassing other exceptionally durable releases.
This fact concerns U.S. sales rather than worldwide sales, chart weeks, or certification units. Those measures are related but not identical: certifications can count shipments, while SoundScan figures track reported purchases.