IT dominated to claim the number one spot in the weekend box office, earning an estimated $117 million and accounting for more than 75% of the combined gross for the top twelve films. The impressive weekend set numerous records including preview records for the largest gross for a horror movie, the largest gross for an R-rated film, the largest gross for a September release, and the largest gross for a Stephen King adaptation. It also broke opening weekend records for the largest September opening weekend set by Hotel Transylvania 2 in 2015 with $48.5 million, along with the largest opening weekend for a horror or supernatural film set by Paranormal Activity 3 in 2011 with $52.6 million. It is the second largest opening weekend for an R-rated feature, only behind Deadpool at $132.4 million. It finished with the third-largest opening weekend of 2017, trailing only Beauty and the Beast and Guardians of the Galaxy Vol. 2.
Home Again was the only other new film, earning an estimated $9 million for second place. The Hitman's Bodyguard finished with an estimated $4.85 for third place, nearing a total domestic gross of $65 million. Annabelle: Creation finished in forth with an estimated $4 million, bringing its domestic earnings to $96.2 million so far in three weeks. Wind River rounded out the top five with an estimated $3.2 million, for a domestic total of $25 million.