The first six months of a puppy’s life run on a schedule that will not wait for you to catch up. The socialization window that shapes how your dog behaves for the rest of its life is open for a matter of weeks, teething starts and ends on its own timeline, and vaccine rounds are time sensitive. Enter your puppy’s age and see exactly what matters right now, what is coming next, and what you may have already missed.
Not sure exactly? Roughly: 2 months is about 9 weeks, 3 months is about 13 weeks, 4 months is about 17 weeks, 6 months is about 26 weeks.
Why the first 16 weeks outweigh almost everything that comes after
A dog's temperament is not fixed at birth. It is shaped in large part by what happens during a narrow window early in life, roughly weeks 8 to 16, when the puppy brain is unusually receptive to new experiences without defaulting to fear. Calm, positive exposure to people, dogs, sounds, surfaces and everyday situations during this stretch is one of the strongest predictors of a confident adult dog. Miss it, and the same work later takes far longer and rarely closes the gap completely.
Vaccine timing complicates this. Full protection typically is not in place until after the core series finishes, often around 16 weeks, which is also roughly when the socialization window itself closes. The practical answer most vets and behaviorists give is controlled exposure: carried outings, well managed puppy classes, and vaccinated dogs in private settings, rather than waiting until 16 weeks to start.
Teething is not a training problem
The mouthiness that shows up between 12 and 20 weeks is physical, not behavioral. Baby teeth are loosening and falling out, and adult teeth are pushing through underneath. A puppy in this stretch needs something appropriate to chew, not a correction for chewing. Punishing normal teething behavior tends to teach a puppy to hide the chewing rather than stop it.
How this timeline was put together
The stage boundaries reflect commonly cited veterinary and canine behavior guidance on socialization timing, vaccine scheduling norms and typical teething progression. Exact vaccine schedules vary by vaccine brand, region and individual risk, so treat the vaccine references here as a general guide and confirm the specifics with your own vet. This tool does not diagnose or treat anything; it is a planning aid.
Frequently asked questions
What if I don't know my puppy's exact age in weeks?
Use the closest estimate from your puppy's birth date or from what the breeder or shelter told you. Being off by a week rarely changes which stage you are in, since the stages overlap on purpose.
I missed part of the socialization window. Is it too late?
No single missed week ruins a dog. Exposure after 16 weeks still helps, it simply builds confidence more slowly than it would have earlier. Keep going rather than treating the window as an all or nothing deadline.
When can my puppy go to a dog park?
Only once your vet confirms the core vaccine series is complete, which is usually around 16 weeks but depends on the schedule your vet is using. Ask at your next visit rather than guessing from age alone.
How is this different from the Dog Adolescence Timeline tool?
This tool covers the early developmental stretch: socialization, vaccines and teething, from birth through roughly 26 weeks. The Dog Adolescence Timeline picks up from there and covers the behavioral regression that comes with puberty, typically from around 6 months onward.
This tool offers general planning guidance based on commonly cited developmental and veterinary references and does not replace advice from your own veterinarian, especially for vaccine timing, which varies by brand and region. Last reviewed: 25 September 2026.