Metallica became the first album in the Nielsen SoundScan era to sell 16 million copies in the United States.
The self-titled 1991 record achieved this distinction after years of sustained sales rather than a short-lived release-week surge. Nielsen SoundScan began tracking US music sales in 1991, the same year Metallica arrived, making the album a landmark for the modern measurement era.
By 2016, the album had sold about 16.4 million copies in the United States, according to the album's documented sales history. It also became the best-selling album in the United States since Nielsen SoundScan tracking began, surpassing other major long-running releases.
The result reflects the album's unusually durable catalogue life. Its five major singles kept songs in radio and video rotation, while touring and later reissues introduced the record to new generations. The album was certified 2× Diamond by the RIAA in 2025 for US shipments of 20 million copies, further confirming its exceptional commercial reach.