When do puppies stop growing?

On this page

1. Timeline by size
2. Growth plates and exercise
3. Weigh every 3 to 4 weeks
4. WALTHAM growth charts
5. Predicting adult weight, with caveats
6. Switching to an adult target

It depends on adult size. Toy and small breeds reach adult height by about 6 to 8 months and adult weight by 10 to 12. Medium breeds finish around 12 months. Large breeds reach height by 12 months and keep filling out to 15 to 18. Giant breeds grow until 18 months and mature to 2 or 3 years. Growth plates close on the same schedule, which is why puppies of big breeds should not jog until well after their first birthday, and why a puppy's ideal weight is a moving target until then.

Timeline by size

Ranges are from the AKC's guidance on puppy growth and the WALTHAM growth charts. Mixed breeds follow the size they are heading toward; if you do not know, the size of the paws and the parents are the usual clues, and the vet's growth chart is the honest one.

Growth plates and exercise

A puppy's long bones grow from cartilage plates near each end, which are soft until they turn to bone at the ages in the last column. Repetitive impact on open growth plates, from jogging, jumping down from furniture or cars, stairs by the dozen, marathon fetch, is linked to joint disease later, and large-breed puppies are the most exposed because they weigh the most while their plates are open longest. The AKC's rule is no jogging before the plates close; for a Labrador that means well past a year. The walking limits by month are in How much should you walk a puppy?.

Weigh every 3 to 4 weeks

Puppies gain fast: a Labrador puppy adds around two pounds a week for months. Weigh every three to four weeks at home (methods for small and squirmy dogs are in How to weigh a dog at home) and at every vet visit, and write it down with the date. The point is not the number; it is the curve. A puppy tracking steadily along a line is fine whatever the line; one that jumps up or falls off across a few weeks is worth a call.

WALTHAM growth charts

The WALTHAM Petcare Science Institute publishes puppy growth charts by adult size, the dog equivalent of the percentile charts paediatricians use. Your vet plots your puppy's weight on them and can see, months before it shows in the mirror, whether the puppy is growing too fast (a real problem in large breeds: too much food and too much calcium accelerate growth and stress joints) or too slowly. Ask to see the chart; it is the best single answer to "is my puppy the right weight".

Predicting adult weight, with caveats

The folk formulas: for small breeds, roughly double the weight at four months; for medium breeds, double the weight at four to five months; for large breeds, double the weight at five to six months. They are rough because puppies grow in spurts and mixed breeds are unpredictable. Better predictors, in order: the parents' weights, the breed standard range (in How much should my dog weigh?), and the growth-chart trajectory. The honest answer to "how big will he get" from a vet is usually a range and a shrug, and the range is enough to plan the walks.

Switching to an adult target

Once growth ends, the weight target stops moving and the adult rules take over: body condition scoring (ribs, waist, tuck), an ideal weight set with the vet, and the adult ration computed for that ideal rather than the puppy ration that fuelled growth. The switch matters: puppies fed on the growth multiplier past adulthood get heavy fast, and the calorie needs calculator shows how large the drop is, from two or three times the resting requirement down to 1.6. Update the height in your walk tracker too, since a taller dog takes longer strides; then measure the new adult baseline with the method in How much should you walk your dog?.

Frequently asked questions

How big will my puppy get?

The most reliable predictor is the parents, then the breed range, then the growth chart your vet plots. Folk rules (double the weight at four months for a small breed, at five to six months for a large one) are rough at best and wrong for mixes.

When is a dog fully grown?

Height and length finish first, weight and muscle later. Small breeds are physically adult around 10 to 12 months, medium around 12 to 15, large around 18, and giant breeds keep filling out to 2 or 3 years.

When do a puppy's growth plates close?

Around 8 to 12 months in small breeds and 14 to 18 months or later in large and giant breeds. Until then, avoid repetitive impact: jogging, jumping down, long stair sessions, marathon fetch.

How often should I weigh a puppy?

Every three to four weeks, and at every vet visit, so the vet can plot the curve against a growth chart. A puppy that jumps or drops across percentile lines is worth a conversation.

This guide is general information from published veterinary and scientific sources, not veterinary advice. Every dog is different: for exercise, weight or feeding decisions, talk to your vet. Pawdometer never gives diet advice.