Millie Bobby Brown was born on 19 February 2004, so her age depends on the year you are asking about. As of early 2026, she is 21 years old.

Exact birth date

  • Millie Bobby Brown’s birthdate is 19 February 2004.
  • She was born in Marbella, Andalusia, Spain, to British parents.

How old was Millie Bobby Brown?

Because the question is “how old was Millie Bobby Brown,” here are a few key points using that birth year:

  • During the first season of Stranger Things in 2016, she was 12 years old.
  • When she became one of Time’s 100 most influential people in 2018, she was 14.
  • When she turned 18, it was February 2022; when she turned 21, it was February 2025.

Current age reference

  • Biographical references list her as 21 years old, consistent with a 2004 birth year.
  • Recent coverage of her press statements and tabloid criticism also notes that she is 21.

TL;DR: Millie Bobby Brown was born on 19 February 2004, so “how old was Millie Bobby Brown” depends on the moment in time, but right now she is 21.

Information gathered from public forums or data available on the internet and portrayed here.