While filming doesn't begin until next year, it's being reported the combined production budget for Avengers: Infinity War Part 1 and Part 2 is an incredible $1 billion. The two films will be shot back to back over a nine-month span, albeit there is no sign of a script or plot points yet. That means the presumed budget is, for now, mere speculation or rumor. The total production budget for Avengers: Age of Ultron was roughly $280 million, so if the noticeable leap for the two upcoming flicks is correct, they seem to be sparing no expense.
According to Bleeding Cool, who reported the $1 billion allotment, "The above the line costs, that paid to the screenwriter, director, producers and principal actors will be a cool four hundred million dollars alone. And of the actor budget, Robert Downey Jr. gets half."
Avengers: Infinity War Part 1 hits theaters on May 4, 2018, with Avengers: Infinity War Part 2 arriving May 3, 2019.