Though it wasn't directly stated early in the MCU, Thor mentioned to Rocket Raccoon in Avengers: Infinity War that he was 1,500 years old. With that revelation, it's simple to yield the character's age throughout the cinematic franchise due to his 518 AD birth year.

How old are Thor and Loki in human years?

Asgardians live for about 5,000 years and Loki's only been around for 1,070 of those years, which, relative to humans, makes him about 21.4 years old. Thor, on the other hand, is 1,500 years old, which makes him about 30 years old in human years.

What is Thor's real age?

After Thor encounters the Guardians of the Galaxy in a pivotal moment, he begins explaining how many foes he's fought over the years. To help illustrate his point more clearly, he reveals that he is 1,500 years old.