While 3:02 may not be the exact running time, it's close, according to sources. Disney declined to comment.

Disney and Marvel will likely forfeit one showing a day on any given screen because of the run time. Box office analysts say they can make up for this by playing Endgame in as many auditoriums as possible within one complex.

Avengers: Endgame, the 22nd installment in the MCU, is the culmination of an 11-year journey that started with Iron Man, and is a direct sequel to last year's Avengers: Infinity War. The Russo brothers shot the films back to back.

Infinity War — previously the longest MCU title with a running time which ran two hours and 29 minutes — launched to $257.7 million in late April 2019, the biggest domestic opening of all time. It went in to earn $2.04 billion globally, the fourth-best of all time, unadjusted.

In 2012, Warner Bros. and Christopher Nolan's The Dark Knight Rises ran two hours and 45 minutes.

And among movies sporting a running time of three hours or more, James Cameron's Titanic (3:14) grossed $2.18 billion at the worldwide box office, unadjusted for inflation. It remains the No. 2 pic of all time globally.

Peter Jackson's The Lord of the Rings: The Return of the King (3:20) earned $1.11 billion globally, the best of the series (the first two films were just under three hours).

In terms of the MCU universe, Captain Marvel, now in theaters, runs two hours and four minutes. The Avengers was two hours and 23 minutes, while Avengers: Age of Ultron was two hours and 21 minutes.