'Avengers: Endgame' is destined to smash box office records this weekend, but it won't surpass $300 million in US debut

Even with a record number of presale tickets and additional showings, "Endgame" probably won't earn much more than the predicted range of $260 million and $285 million for its U.S. debut. Although some have speculated the film could reach or surpass the $300 million mark, it's not likely.