When Do Dogs Stop Growing?
It depends on size. Small breeds usually finish growing around 6 to 8 months, medium breeds around 12 months, and large breeds between 12 and 18 months. Giant breeds keep growing the longest, often not reaching full size until 18 to 24 months. Bigger dogs take longer because their larger bones need more time, and dogs keep filling out with muscle for a while after their skeleton stops growing.
It depends mostly on your dog’s adult size. As a rule, the bigger the dog, the longer it takes to finish growing - small dogs are done in well under a year, while giant breeds can still be growing at two years old.
Growth timeline by breed size
| Size | Roughly finishes growing | Examples |
|---|---|---|
| Small / toy | 6–8 months | Chihuahua, Yorkshire Terrier, Pomeranian |
| Medium | ~12 months | Beagle, Border Collie, Cocker Spaniel |
| Large | 12–18 months | Labrador, German Shepherd, Boxer |
| Giant | 18–24 months | Great Dane, Mastiff, Saint Bernard |
These are guides, not guarantees - individual dogs and mixed breeds vary.
Why big dogs take longer
Larger dogs have bigger bones that simply need more time to lengthen and strengthen. Their growth plates - the soft areas at the ends of the bones - stay open longer and close later. This is also why large and giant breeds should stay on large-breed puppy food and avoid too much high-impact exercise while young: it supports steady, healthy bone growth.
Height first, then bulk
Dogs usually reach their full height before they reach their full weight. Even after the skeleton has stopped growing, a young dog continues to fill out with muscle and reach adult body condition - so a lanky, gangly “teenager” will keep maturing in shape for several more months.
How to estimate your puppy’s adult size
- Paws that look oversized often hint that a puppy still has growing to do.
- Parents’ size is the best predictor for purebreds.
- Breed and weight charts from your vet can track whether growth is on track.
- For mixed breeds, a DNA test or your vet’s estimate can give a rough idea.
When to switch to adult food
Move from puppy to adult food once growth is finishing - around 8–12 months for small breeds and closer to 12–24 months for large and giant breeds. Your vet can confirm the right timing, since switching too early or too late both have downsides for big dogs.
References
- When Do Dogs Stop Growing? - American Kennel Club
- When Do Dogs Stop Growing? - PetMD
- Puppy Growth and Maturity - VCA Animal Hospitals
This article is general information, not veterinary advice. Ask your vet about your puppy’s growth and feeding plan.
