How this puppy weight predictor works
Puppies don't grow in a straight line. They put on weight fast in the first few months, then slow down as they approach adult size. Small breeds finish growing much earlier than big ones. A Yorkie is close to full size by 9 months, while a Great Dane is still filling out at 18 months or more.
The calculator uses growth curves for five size classes (toy, small, medium, large and giant), based on published studies that weighed thousands of puppies. It looks up what share of adult weight a puppy of that size class usually has at your puppy's age, then divides the current weight by that share. If you pick "work it out for me", it tries each size class and settles on the one your puppy's numbers fit best.
Typical share of adult weight by age
| Age | Toy | Small | Medium | Large | Giant |
|---|---|---|---|---|---|
| 8 weeks | 28% | 24% | 22% | 17% | 12% |
| 12 weeks | 42% | 38% | 35% | 28% | 20% |
| 16 weeks | 56% | 52% | 48% | 40% | 30% |
| 6 months | 81% | 77% | 73% | 63% | 53% |
| 9 months | 97% | 93% | 90% | 82% | 72% |
| 12 months | 100% | 99% | 98% | 93% | 85% |
Breed-specific puppy weight charts
Want to see the expected weight at every age for your breed? Pick one:
- Labrador Retriever
- Golden Retriever
- German Shepherd
- French Bulldog
- Goldendoodle
- Shih Tzu
- Yorkshire Terrier
- Cane Corso
- Beagle
- Boxer
- Chihuahua
- Cavapoo
- Cockapoo
- Bernedoodle
- Boston Terrier
- Siberian Husky
- Great Dane
- Dachshund
- Australian Shepherd
- American Pit Bull Terrier
Tips for an accurate result
- Weigh at the same time of day, before a meal. The easy way: weigh yourself holding the puppy, then subtract your own weight.
- Re-run the calculator every few weeks. Predictions get sharper as your puppy gets older.
- Don't feed for a bigger dog. Overfeeding doesn't change a puppy's genetic size, it just adds fat and strains growing joints, especially in large breeds.
Frequently asked questions
How accurate is a puppy weight calculator?
For purebred puppies weighed after about 12 weeks, estimates usually land within 10 to 15% of the final weight. They are less reliable for very young puppies and for mixed breeds, because the growth curve depends on the adult size.
How can I tell how big my mixed breed puppy will get?
Use the calculator with "work it out for me", then sanity-check the result against the parents. Paw size is a myth-ish guide at best. A DNA test that identifies the main breeds can help narrow the range.
Is it true that a puppy doubles its 16-week weight?
Roughly, for small and medium dogs, which are about half their adult weight at 16 weeks. Large and giant breeds are only 30 to 40% of their adult weight at that age, so doubling would underestimate them.
At what age is a puppy half its adult weight?
Around 14 to 16 weeks for toy and small breeds, 16 to 18 weeks for medium dogs, about 20 weeks for large breeds and close to 6 months for giant breeds.