Avengers: Endgame is three hours and two minutes long. That is 20 minutes shorter than The Godfather Part II. If there is a post-credits scene, you are legally obligated to sit through at least 20 minutes of that 182-minute runtime.
It could have been even longer.
The directors were asked if they would be releasing a six-hour cut of Endgame. “I think the longest [cut] we ever had was like 3 hours and 40 minutes, [but] I think those 40 minutes deserve to be on the editing floor,” Joe said. The only way it could have been six hours is “if we did a supercut of Infinity War and Endgame,” Anthony added. “You have the director’s cut. That’s it. There’s nothing else, sorry,” Joe confirmed