Which Harry Potter book was the first in the series to sell more than 10 million copies worldwide on its first day?

Harry Potter and the Deathly Hallows was the first Harry Potter book to sell more than 10 million copies worldwide on its first day.

The seventh and final main Harry Potter novel was published on 21 July 2007. Its simultaneous release created enormous anticipation because readers knew it would conclude Harry’s central conflict with Lord Voldemort. Publishers reported more than 11 million copies sold in the United States and United Kingdom during the first 24 hours.

Those figures are launch-sales records for the book’s initial markets and should not be confused with its lifetime sales or the total circulation of the entire Harry Potter series. Different editions and territories also have separate sales data.

The novel follows Harry, Ron, and Hermione as they leave Hogwarts and search for Voldemort’s Horcruxes. Its title refers to three legendary magical objects: the Elder Wand, the Resurrection Stone, and the Cloak of Invisibility.