Metallica became the first album in the SoundScan era to sell 16 million copies in the United States.
Nielsen SoundScan began tracking U.S. music sales in 1991, the same year Metallica released its self-titled fifth album. By 2016, the record had sold about 16.4 million copies in the United States, making it the best-selling album there since SoundScan tracking began.
Its sales were unusually broad across formats. About 5.8 million of those U.S. purchases were cassette copies, an important detail because the album arrived when cassettes remained a major way for listeners to buy recorded music.
The achievement is distinct from worldwide sales and later certification milestones. Metallica has sold more than 30 million physical copies worldwide, while the U.S. SoundScan record refers specifically to measured American sales. The album was later certified double Diamond by the RIAA in 2025 for shipping 20 million units in the United States.