Will Byers was 12 years old when he went missing in Stranger Things season 1.

Will’s age when he disappeared

  • The in‑universe missing person posters shown in season 1 list Will as 12 years old at the time he vanished.
  • A popular fan discussion points out that even though a character refers to him as an “11‑year‑old boy,” the props and on‑screen details confirm he was actually twelve when he went missing.

Why there’s confusion about his age

  • Fans noticed dialogue where Joyce calls him an 11‑year‑old, which contradicts the age shown on the missing posters.
  • Forum discussions suggest this is likely a writing or continuity slip rather than an in‑story mystery, though some viewers enjoy speculating that it might tie into broader series themes about memory and time.

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