A dog is usually considered a puppy until roughly 1–2 years old, depending a lot on their size and breed.

Puppy vs adult: quick scoop

  • Most dogs are in puppyhood from birth up to about 12–24 months.
  • Small breeds often stop being puppies sooner (under a year), while large and giant breeds stay “puppy” much longer.
  • Physically, many dogs look grown before they’re mentally and emotionally mature, so they can act puppy‑ish even after their “official” puppy age.

Rough age guide by size

  • Extra‑small & small breeds (Chihuahua, Pug, Dachshund): usually considered fully grown around 9–12 months.
  • Medium breeds (Bulldog, Aussie Shepherd): often mature around 12–18 months.
  • Large breeds (Golden, German Shepherd): often “puppies” until about 18–24 months.
  • Giant breeds (Great Dane, Mastiff): commonly stay in puppy growth stages until around 2 years old.

Why it matters

Knowing how long your dog is a puppy helps you:

  • Plan puppy food vs adult food (large/giant breeds especially need the right puppy formula longer).
  • Set expectations for training, energy, and “teenage” behavior, which often runs from about 6–18+ months.

Many owners casually call their dogs “puppies” until at least 2 years old, especially for big, goofy breeds that stay playful and bouncy.

TL;DR:
For most dogs, think of “puppy” as anywhere up to about 1 year for small breeds and up to about 2 years for large and giant breeds.

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