By the PupGauge editorial team · Last reviewed October 2026 · Based on published growth research (see sources) and our methodology. General information, not veterinary advice.
Quick answer
Most dogs reach their full height at 9–15 months, but the exact age depends on size: toy, small and medium dogs finish around 9–12 months, large dogs at 11–15 months, and giant breeds can keep filling out until about 24 months.
“Full grown” is not one birthday. A Chihuahua can look like an adult by its first birthday, while a Great Dane may still be adding muscle and chest depth at two. This guide explains what actually stops when a dog stops growing, how long each size group takes, and how to tell from your own puppy’s weigh-ins that growth is slowing down.
Typical Age at Full Size, by Group
| Group | Adult weight | Usually full size |
|---|---|---|
| Toy | up to 6.5 kg (14 lb) | 9–12 months |
| Small | 6.5–15 kg (14–33 lb) | 9–12 months |
| Medium | 15–25 kg (33–55 lb) | 9–12 months, sometimes up to 14 |
| Large | 25–40 kg (55–88 lb) | 11–15 months |
| Giant | 40–80 kg (88–176 lb) | 15–24 months |
The toy-to-large windows follow Hawthorne et al. (2004), the growth study behind our Puppy Weight Calculator. Those dogs were weighed repeatedly from birth, so the ages describe when weight gain levelled off, not when the dog looked grown-up. Treat each window as a typical range: a lean, slow-maturing individual can finish later and a fast-maturing one earlier.
What Actually Stops Growing, and When
Three things happen on slightly different schedules, which is why a puppy can look “done” and still change shape for months.
Height and bone length
Bones lengthen at growth plates, soft zones of cartilage near the ends of the long bones. Once a plate closes, that bone cannot get longer. Small dogs close their plates early, often before their first birthday. In large and giant dogs it takes noticeably longer, and some plates are still open at 12–18 months, which is why heavy impact and over-feeding matter more in these breeds (see growing a large-breed puppy safely).
Body weight
Weight usually keeps rising after height has stopped. A Labrador may reach its adult height at around 10–12 months but keep adding muscle and rib-cage depth well into its second year. Weight tends to plateau first in small breeds and last in giant ones.
Chest, muscle and coat
The last changes are cosmetic: a deeper chest, broader skull, thicker adult coat and heavier muscling. A German Shepherd at 14 months can look leggy and narrow, then look like a different dog by 24 months. This “filling out” is normal and does not mean the dog is underweight, as long as you can still feel the ribs under a thin layer of fat (the body condition score guide shows how to check).
Examples by Breed
Breed gives a better clue than size group alone. These are typical ranges and not guarantees.
| Breed type | Height stops | Weight and body keep changing |
|---|---|---|
| Chihuahua, Yorkshire Terrier, Pomeranian | about 6–9 months | to about 12 months |
| Beagle, Cocker Spaniel, French Bulldog | about 9–12 months | to about 12–15 months |
| Border Collie, Boxer, Staffordshire types | about 10–14 months | to about 18 months |
| Labrador, Golden Retriever, German Shepherd | about 10–14 months | to about 18–24 months |
| Great Dane, Mastiff, Saint Bernard | about 15–18 months | to about 24 months or longer |
You can see month-by-month weights for two popular breeds in our Labrador puppy weight chart and German Shepherd puppy weight chart.
Signs Your Puppy Is Nearly Finished Growing
- Weight gain slows. Weekly gains shrink to small changes, then to almost nothing. A smooth, flattening curve is the clearest sign.
- Appetite settles. The ravenous phase eases, and many owners can move from puppy food to adult food within the window your vet advises.
- Proportions even out. Legs, body and head start to look balanced rather than lanky or oversized.
- Clothes and gear stop fitting differently. A harness or collar size that lasts several months in a row is a practical signal.
Weigh your puppy every two to four weeks on the same scale and note the result. Plot the points, or enter them into the puppy weight chart for your size group, and you will see the curve flatten before your eyes can.
What Can Change the Timeline
- Genetics and breed. The biggest factor by far. Mixed breeds follow the size of the larger ancestors more than the smaller ones.
- Nutrition. Under-feeding can delay growth. Over-feeding does not speed up height but increases weight and joint stress, especially in large breeds.
- Spay and neuter timing. Neutering before the growth plates close can lengthen the time bones keep growing, which is one reason vets increasingly tailor timing to breed size. Discuss the timing with your vet.
- Health. Parasites, illness or chronic digestive problems can slow growth and are worth investigating if your puppy lags well behind the chart.
The full picture is covered in our guide to how big your puppy will get.
Worked example: A 12-week-old mixed breed puppy weighs 7 kg and its parents are medium-sized. Medium dogs usually finish growing around 9–12 months, so expect weight gain to slow noticeably in about 6–8 months. If it is still gaining quickly at 14 months, check with your vet and use the calculator to compare against the expected range.
Frequently Asked Questions
At what age is a dog considered fully grown?
Most dogs are considered fully grown at 12–18 months, but the range runs from about 9 months for small dogs to about 24 months for giant breeds. Emotional maturity often lags behind physical maturity by another year.
Do dogs grow after 12 months?
Yes, large and giant breeds usually do. Medium and small dogs mostly stop growing taller by 12 months, but muscle, chest depth and coat can still change for several more months.
Can paw size tell me how big my puppy will get?
Paws are only a rough hint. Large paws on a young puppy often suggest a larger adult, but breed and parents’ sizes are far better predictors.
When can I switch from puppy food to adult food?
Small breeds often switch at about 9–12 months and large or giant breeds at about 12–18 months. Your vet can confirm the right time for your puppy’s body condition and breed.
Does neutering stop a puppy from growing?
No. It does not stop growth, but neutering before the growth plates close may extend the growth period in some dogs. Ask your vet about timing for your breed.
How can I check my puppy is growing normally?
Weigh it every two to four weeks and compare against a breed or size-group chart. Steady gain that slows with age is normal; sudden drops, no gain, or very rapid gain are reasons to call the vet.
Related Guides, Charts and Calculators
- Puppy Weight Calculator – likely adult weight from age, weight and breed or size group.
- Puppy Weight Chart by Age and Size – typical weights by age for each size group.
- How Big Will My Puppy Get? – every method for estimating adult size.
- Growing a Large-Breed Puppy Safely – feeding and exercise for large and giant puppies.
- Dog Life Stages Explained – what each stage means for care.
- Dog Age Calculator – life stage and human-year equivalent.
Sources and Method
Figures on this page come from published research and breed standards rather than guesswork: Hawthorne et al. (2004) growth curves for dogs of different sizes; Salt et al. (2017) puppy growth standards; the 2019 AAHA Canine Life Stage Guidelines; AKC breed standards; and the WALTHAM puppy growth charts. Every number is a typical range, and individual dogs vary. How PupGauge turns these sources into estimates is explained on the methodology page, and your vet can confirm whether your own dog is on track.