Puppy Weight Calculator
How Big Will My Puppy Get?
Predict your puppy's adult weight using breed-specific growth curves and vet-approved formulas. Works with 346+ breeds.
Optional: Improves accuracy by 40%
Enter weight and age (min 8 weeks) to get started
When Will My Puppy Stop Growing?
Wondering when your puppy will finally stop growing? It really comes down to their breed size. Little dogs like Chihuahuas or Yorkies shoot up fast, often hitting their full adult weight by the time they're 10 or 12 months old. Big dogs like Labs or Great Danes, on the other hand, take their time. A giant breed can keep filling out until they're a full two years old. Knowing what to expect helps you pick the right food, buy a crate they won't immediately outgrow, and make sure they're on a healthy track.
Toy/Small
Adult by 10-12 months
Medium
Adult by 12-15 months
Large
Adult by 15-18 months
Giant
Adult by 18-24 months
How Our Predictor Works
To figure out how big your dog will get, our calculator looks at their current age and weight, and compares it to standard veterinary growth curves. For instance, a 16-week-old small breed puppy is already at about 50-60% of their final weight. A giant breed puppy at that exact same age? They're only at about 25-30%.
If you have a purebred dog, the estimate is usually pretty spot-on because we have decades of data on exactly how those breeds grow. Mixed breeds are a bit of a wildcard, but by matching them to the closest size category, we can still give you a very solid estimate of their final adult weight.
What Affects Your Dog's Final Size?
Genetics
Mom and dad play the biggest role here. If you know how big your puppy's parents are, you've got a great clue about their future size (though mixed breeds can always surprise you!).
Diet
What you feed your puppy matters. Overfeeding a puppy won't make them grow into a bigger adult dog. It just makes them grow too fast, which can cause serious joint problems later.
Spaying & Neutering
Did you know that fixing a dog early can actually make them slightly taller? Taking away sex hormones delays the closure of their growth plates, giving their bones a bit more time to grow.
Boys vs. Girls
Just like with people, male dogs almost always end up taller and heavier than females. This difference is way more noticeable in big dogs than it is in toy breeds.
Growth Milestones by Size
Under 20 lbs
Little guys like Chihuahuas and Yorkies grow up fast. They usually double their 8-week weight by the time they hit 12 weeks, and they're about 75% done growing by 6 months. By 10 to 12 months, they're officially adults.
20-50 lbs
Dogs like Beagles and Cocker Spaniels take a bit longer. They hit the halfway mark around 14 to 16 weeks and do most of their serious growing between 3 and 6 months. Expect them to top out around 12 to 15 months.
50-100 lbs
Labs, Goldens, and German Shepherds need slow, steady growth to keep their joints healthy. They hit 50% of their adult weight around 4 or 5 months, but they won't be fully filled out until they're at least a year and a half old.
100+ lbs
Great Danes and Mastiffs are the ultimate late bloomers. At 4 months old, they might only be 30% of their final weight! It's super important to keep their growth slow and controlled to prevent hip issues, as they keep growing for a full two years.
Puppy Growth Chart by Breed Size
This growth chart shows the approximate percentage of adult weight a puppy reaches at each age milestone. Use this alongside our calculator for the most accurate predictions.
| Age | Toy/Small <20 lbs | Medium 20-50 lbs | Large 50-100 lbs | Giant 100+ lbs |
|---|---|---|---|---|
| 8 weeks | 22-30% | 18-25% | 15-20% | 10-15% |
| 3 months | 35-45% | 28-35% | 22-30% | 18-25% |
| 4 months | 50-60% | 40-50% | 30-40% | 25-30% |
| 6 months | 75-85% | 60-70% | 50-60% | 40-50% |
| 9 months | 90-95% | 80-90% | 70-80% | 60-70% |
| 12 months | ~100% | 90-95% | 85-90% | 75-85% |
| 18 months | 100% | ~100% | 95-100% | 90-95% |
| 24 months | 100% | 100% | ~100% | ~100% |
Source: Veterinary growth curve data compiled from breed standards. These are approximate ranges. Individual puppies may vary. Consult your veterinarian for specific guidance.
Feeding Your Puppy for the Best Growth
What you put in their bowl right now makes a huge difference. Growing puppies burn a ton of energy, often needing two to three times more calories per pound than adult dogs do. To make sure you're not underfeeding (or overfeeding!) them, plug their numbers into our Dog Calorie Calculator. If you're looking for a good brand to switch to, take a look at our Best Dog Food guides.
It's a really common myth that giving a puppy extra food will make them grow into a bigger, stronger dog. It won't. Overfeeding just forces their bones to grow too fast, which is terrible for their joints, especially if they're a large or giant breed. Your dog's genetics have already decided how big they'll get, so just focus on keeping them at a healthy weight while they get there.
A Quick Note From Us
We built this calculator using standard veterinary growth charts, but remember that every puppy is unique. Just like kids, some hit growth spurts early, and some are late bloomers. This tool is meant to give you a really good estimate, but it shouldn't replace advice from your vet. If you're worried about your puppy's weight or growth, definitely give your vet a call.
Frequently Asked Questions
How can I predict my puppy's adult weight?
A common formula: Adult weight = Current weight ÷ Current age in weeks × 52. However, breed size matters - toy breeds reach adult weight by 10 months, while giant breeds may grow until 18-24 months.
When do puppies stop growing?
Small breeds stop growing at 10-12 months, medium breeds at 12-15 months, large breeds at 15-18 months, and giant breeds continue growing until 18-24 months.
How accurate are puppy weight predictions?
Predictions are most accurate for purebred puppies. For mixed breeds, look at paw size and parent weights if known. Predictions become more accurate as the puppy ages.
Why is my puppy smaller or larger than predicted?
Factors like nutrition, health, genetics, and whether they're neutered can affect final size. Proper nutrition is crucial - both underfeeding and overfeeding can affect growth.
Should I feed my puppy more to help them grow bigger?
No, overfeeding can lead to orthopedic problems, especially in large breeds. Feed according to guidelines and let your puppy grow at their natural pace.
How do I know if my puppy is a healthy weight?
You should feel ribs easily without pressing hard, see a waist from above, and see an abdominal tuck from the side. Your vet can assess body condition score.