What should I expect as my puppy grows, and when should I call the vet?

Short answer: puppies change quickly, but not on a fixed timetable. A puppy should stay with their mother until at least 8 weeks. Baby teeth are replaced by adult teeth by about 6 to 7 months. Small dogs are usually full size between 6 and 12 months, and large dogs can take up to two years. If your puppy seems to be growing differently from what you expected, a quick call to your vet is the simplest way to know.

The first weeks: staying with mum

A puppy should stay with their mother and littermates until they are at least 8 weeks old. If you are choosing a puppy, ask to see the puppies with their mother, and ask how old they are. A good breeder will not hand a puppy over earlier. If someone offers you a younger puppy, it is fine to walk away. Once your puppy is home, a first vet visit is a good next step, and your vet can plan check-ups with you.

Teeth and chewing

Puppies lose their baby teeth and grow adult teeth. The adult teeth usually start to come in at around 4 to 5 months, and by about 6 to 7 months the full adult set is in. Our guide to puppy biting in the first six months has a practical plan for mouthing. Your vet can look at your puppy's mouth at check-ups, and our dental care basics cover how to start caring for those new teeth.

How fast they grow

Small breeds are usually full size between 6 and 12 months. Medium dogs are usually there by about a year. Large and giant breeds keep growing longer, often to 18 months and sometimes up to 2 years. Your puppy's breed or mix gives a rough guide only, and your vet can tell you what to expect for your dog. Growing puppies need good food in the right amounts, and our guide to feeding a growing puppy helps you set up a routine.

Rest and exercise while they grow

Growing is tiring. Puppies need a lot of sleep, and they do better when they can nap without being disturbed. An overtired puppy often gets silly and mouthy, so a quiet rest is often what helps. Their joints and bones are still developing, so keep exercise gentle and build up slowly until they are fully grown. Skip high-impact things like long runs or agility until your vet says your puppy is ready. If you wonder whether your dog is sleeping too much, our sleep guide can help.

When to ask your vet

Take a breath, then give your vet a call if your puppy seems to be growing very differently from other puppies of their kind, is limping, is eating or drinking much less than usual, or just seems off to you. Your vet will tell you whether anything more is needed. Vaccines, worming and flea and tick care follow your vet's schedule, and our guide to fleas, ticks, worms and vaccines explains the basics. Early socialisation also matters, and puppy socialization without flooding shows how to keep it gentle.

Sources: PDSA, getting a puppy: pdsa.org.uk. Dogs Trust, getting a dog responsibly: dogstrust.org.uk. Blue Cross, buying a puppy: bluecross.org.uk. RSPCA, finding a good breeder: rspca.org.uk. MSD Veterinary Manual, dental development of dogs: msdvetmanual.com. VCA Animal Hospitals: teeth and teething, puppy growth and maturity, puppy sleep. PDSA, exercising your puppy. Blue Cross, puppy exercise. RSPCA, caring for your puppy.

General education only, not veterinary advice or a plan for your individual dog. If you are worried about your puppy's growth or health, please contact a vet. See our legal page.