Green Day formed in 1987, so as of 2026 the band is about 39 years old as a group.

Quick Scoop: How old is Green Day?

  • Green Day started in 1987 in the East Bay / Rodeo, California punk scene, originally under the name Sweet Children before switching to Green Day a couple of years later.
  • Counting from 1987 to 2026, the band has been active for roughly 39 years.
  • Billie Joe Armstrong and Mike Dirnt were mid-teens when they started the band, which is why Green Day is now seen as one of the “elder statesmen” of pop‑punk while still touring and releasing music decades later.

In fan communities, people often say they “grew up with Green Day” and now feel old realizing the band itself is pushing 40 years of history.

TL;DR: Green Day is about 39 years old as a band in 2026, having formed in 1987.

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