How Long Do Puppies Grow?

Name: How Long Do Puppies Grow?
Creator: Dr. Zubair Khalid

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-10-02

Puppies keep growing until their growth plates close, and that timing depends mostly on breed size. Small breeds often finish by 6 to 12 months, while large and giant breeds can keep growing for 18 to 24 months. So the honest answer to how long do puppies grow is: it depends on the dog in front of you.

This article is educational and is not a substitute for veterinary diagnosis or treatment.

Quick Answer

Growth plate closure, not age alone, marks the end of bone growth. Once the plates close, height is set.
Small dogs (under about 20 pounds adult weight) usually finish growing between 6 and 12 months.
Medium dogs often finish between 12 and 15 months.
Large and giant breeds may keep growing until 18 to 24 months.
Weight gain can continue after height stops, especially in puppies that were underweight early on [1].

How Long Do Puppies Grow to Full Size?

Growth happens in two overlapping phases. First, the long bones lengthen at the growth plates, which are soft cartilage zones near the ends of the bones. Second, the puppy gains muscle, fat, and organ mass. Height stops when the plates close. Weight and body condition can keep changing after that.

The first months matter more than most owners realize. The canine equivalent of the human "first 1000 days" covers pregnancy plus roughly the first two months of life, and this window shapes long-term health [1]. Puppies born small can catch up with good early growth, but low birth weight is linked to a higher risk of becoming overweight later in adulthood [1]. That is one reason your veterinarian tracks weight and body condition at every puppy visit, not just height.

Breed size is the biggest single factor in how long a puppy continues to grow. Miniaturization in dogs is not a simple scaling down of a large dog. Smaller dogs tend to have rounder skull shapes, and head shape does not always scale evenly with body weight [2]. This is why a Chihuahua and a Great Dane follow very different growth curves even though both start as puppies of similar size.

If you are thinking ahead to your dog's adult years, our guide on How Long Do Dogs Live explains how size affects lifespan too.

Growth Plate Closure by Breed Size

Size group	Typical adult weight	Usual age height stops	Notes
Toy and small	Under 20 lb	6 to 12 months	Fastest to mature
Medium	20 to 50 lb	12 to 15 months	Fills out after height stops
Large	50 to 90 lb	15 to 18 months	Slower plate closure
Giant	Over 90 lb	18 to 24 months	Longest growth window

These ranges are general guides. Your veterinarian can narrow them using your puppy's breed, parents, and growth curve.

Step-by-Step: How to Track Your Puppy's Growth

1. Weigh your puppy on the same scale every week or two

Use a baby scale for small puppies and a bathroom scale for larger ones. Weigh at the same time of day, ideally before breakfast. Write the number down. A single weight tells you little. A trend over weeks tells you a lot.

2. Measure height at the withers

The withers is the highest point of the shoulders, between the shoulder blades. Stand your puppy against a wall, place a ruler flat across the withers, and mark the wall. Measure monthly. Height gains slow down before they stop, so a flattening curve is a useful signal.

3. Score body condition, not just weight

Run your hands along the ribs. You should feel ribs easily under a thin layer of fat. You should see a waist in published veterinary research and a slight tuck from the side. Puppies should look lean, not chubby. Excess weight during growth puts extra load on open growth plates.

4. Compare with breed growth charts

Ask your veterinarian for a growth chart matched to your puppy's expected adult size. Charts built for the wrong size category will mislead you. A puppy destined to be 80 pounds should not be judged against a chart for a 10-pound adult.

5. Adjust food as growth slows

Puppies need more calories per pound than adults, but the amount changes as growth rate drops. Overfeeding a large breed puppy can push growth too fast. Ask your veterinarian when to switch from puppy food to adult food. Our article on How Long Should A Puppy Eat Puppy Food covers the timing by size.

6. Keep activity appropriate for open plates

Free play and short walks are fine. Repeated high-impact jumping on hard surfaces is not ideal while plates are open. Jump biomechanics research shows that body weight and body weight-to-height ratio affect how dogs jump, with heavier dogs jumping higher at take-off and landing [3]. A growing large breed puppy carrying extra weight lands harder.

When Do Puppies Stop Growing? Signs to Watch

Height usually stops before filling out does. Here is what to look for.

Height at the withers stays the same for two to three months.
Paws stop looking oversized compared with the legs.
The chest deepens and the body looks less leggy.
Appetite settles into a steady adult pattern.
Coat texture shifts toward the adult coat.

None of these signs is exact on its own. Use them together with your veterinarian's exam.

Signs That Something Is Wrong

Most puppies grow on a predictable curve. A few patterns deserve a call to your veterinarian.

Weight loss or a flat weight curve for two or more weeks.
Limping that comes and goes, especially in a large breed puppy.
Reluctance to walk, climb stairs, or play.
A potbellied look with poor muscle tone.
Sudden swelling, heat, or pain near a joint.
Vomiting, diarrhea, or poor appetite lasting more than a day.
Growth that stalls after an illness or a change in diet.

Some of these can point to nutrition problems, parasites, or orthopedic conditions. Early evaluation is easier on your puppy and your budget.

Common Mistakes Owners Make

Feeding for maximum size

Bigger is not healthier. Pushing rapid growth in large breed puppies can stress developing joints. Feed to a lean body condition and let genetics set the ceiling.

Guessing adult size from paw size alone

Paw size is a rough clue at best. Breed, parents, and the growth curve are better predictors.

Switching to adult food too early or too late

Timing depends on size and expected adult weight. Ask your veterinarian instead of guessing.

Skipping the final puppy visits

Growth plate closure and adult body condition are assessed over time. The last puppy exam often catches issues that early visits miss.

Ignoring early-life weight history

Puppies born small have a higher long-term risk of overweight [1]. If your puppy was the runt or had a low birth weight, tell your veterinarian so the growth plan can account for it.

Assuming all dogs mature the same way

Reproductive maturity and skeletal maturity are different clocks. Female dogs cycle before their bones finish growing. If you want to understand that timeline, see How Long Are Dogs In Heat. Breeding timing is a separate topic, covered in How Long Do Dogs Stay Pregnant.

Supplies and Setup That Support Healthy Growth

You do not need much, but a few items make tracking easier and safer.

A scale you can use at home, plus a wall mark for height.
A growth chart from your veterinarian, matched to expected adult size.
A measuring cup or kitchen scale for food. Weighing kibble is more accurate than scooping.
Non-slip flooring or rugs in high-traffic areas. Slippery floors make growing puppies splay and slip.
A crate sized for the adult dog, with a divider so the puppy is not loose in too much space.
A calendar for vaccine visits and weight checks.

One more note on early life. The first 120 days, counting pregnancy and the first two months of the puppy's life, are the most sensitive window for developmental programming in dogs [1]. Nutrition and early experiences in that window have effects that last into adulthood [1]. If you adopted a puppy with an unknown early history, share that with your veterinarian so they can factor it into the plan.

Limitations and When to Contact a Veterinarian

Growth timelines are estimates, not guarantees. Mixed breeds, puppies with unknown parents, and puppies with early health problems can fall outside the usual ranges. Individual cases need a veterinarian who can examine your puppy, review the growth curve, and check for problems that a chart cannot show.

Call your veterinarian the same day if your puppy:

Refuses food for more than 24 hours.
Has repeated vomiting or diarrhea.
Limps or refuses to bear weight on a leg.
Shows sudden swelling or heat in a joint.
Has a temperature you measured at home that seems high, or seems lethargic and weak.

Go to an emergency clinic now if your puppy:

Collapses, has a seizure, or has trouble breathing.
Has a swollen, painful abdomen with retching.
Cannot stand or cries when moved.
Has been hit by a car or had a major fall.

Schedule a routine visit if:

Growth has stalled for several weeks.
You are unsure when to switch foods.
Your puppy was underweight at birth or in early weeks [1].
You want a body condition score and a growth plan for the next few months.

Your veterinarian sets the feeding plan, the supplement plan, and any medication dose based on your puppy's weight and health. Do not give supplements or pain medications without asking first.

Frequently Asked Questions

Do puppies stop growing at one year?

Many small and medium breeds are close to their adult height by 12 months, but large and giant breeds often keep growing past that point. Weight and muscle fill out after height stops. Use your veterinarian's growth curve instead of a single birthday as the marker.

Can a puppy grow after its first heat cycle?

Yes. Reproductive maturity and skeletal maturity are separate processes, and a female dog can cycle before her growth plates close. That is one reason breeding decisions should wait until she is fully mature. Your veterinarian can advise on the right timing for your dog.

Does neutering change how long a puppy grows?

Neuter status did not show an association with one bone measurement in adult male dogs in a study of radiographic baculum length [4]. Growth plate timing is influenced by hormones, so the age at neutering can matter for some breeds. Discuss the timing with your veterinarian instead of deciding from a general rule.

How accurate are puppy weight calculators?

They give a rough estimate, not a prediction. Accuracy drops for mixed breeds and for puppies with unknown parents. A calculator is a starting point. Your veterinarian's measurements over time are more reliable.

Is it normal for a puppy to look skinny while growing?

Puppies often look leggy and lean during growth spurts, and that can be normal. You should still be able to feel the ribs easily without seeing them sharply. If your puppy looks thin, has a dull coat, or is not gaining weight, have your veterinarian check for parasites and nutrition problems.

Do small dogs really finish growing faster?

Yes, generally. Smaller dogs tend to reach adult height earlier than large and giant breeds. Head shape also varies with size, with smaller dogs more often having rounder crania [2]. This is why growth charts are matched to expected adult size, not just current weight.

When should I worry about a growth spurt?

A sudden, very fast growth spurt in a large breed puppy is worth a call, especially if your puppy limps or seems sore. Rapid growth can stress open growth plates. Your veterinarian can check body condition, diet, and joint health at a routine visit.

References

Developmental programming in dogs. Biology of reproduction, 2026.
Miniaturization in Domestic Dogs: Relationships Among Cranial Shape, Head Indexes, and Body Weight. Veterinary radiology & ultrasound : the official journal of the American College of Veterinary Radiology and the International Veterinary Radiology Association, 2026.
Influence of height, body weight and body weight-to-height ratio on jump kinematics in agility dogs. Research in veterinary science, 2026.
Radiographic reference values for canine baculum length: association with body-weight category in dogs aged at least 1 year. Veterinary research communications, 2026.