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How big will my puppy get?
Not sure of the breed? Leave it blank. The calculator works from your puppy's age and weight.
Ways to estimate adult size, and how much to trust each
Parents' weights. If you know both parents' weights, the average is a sensible starting point, but littermates can land well above or below it.
A DNA test. Breed-mix tests can show which breeds are in the mix, which helps with size. The calculator above doesn't need one.
Paw size and other rules of thumb. We haven't tested paw size against real growth records, so we don't use it.
Your puppy's own weight and age. This is the method used here. Weight at a given age, compared with how dogs of every size typically grow, narrows adult weight down faster than guessing from looks.
What size are you aiming at?
Dogs grow on different schedules by adult size. A small dog is close to its full weight by 6 months, while a giant breed is still gaining at 12. The table shows how much of its adult weight the typical dog in each group has reached.
| Adult weight | At 12 weeks | At 6 months | At 12 months |
|---|---|---|---|
| under 14 lb | 40% | 76% | 94% |
| 14 to 20 lb | 39% | 76% | 95% |
| 20 to 33 lb | 34% | 72% | 95% |
| 33 to 66 lb | 29% | 70% | 93% |
| 66 to 88 lb | 28% | 67% | 91% |
| over 88 lb | 24% | 64% | 91% |
Share of adult weight reached by the typical dog in each group.
Common questions
How accurate is the puppy weight calculator?
We tested it on weigh-ins from dogs the method had never seen. The typical miss was about 11% of adult weight, and roughly 4 in 5 dogs finished inside the range shown. Accuracy improves with age: the typical miss is around 18% at 8 to 11 weeks and 7% after 9 months. The results table on the methods page has the full numbers.
How early can you predict a puppy's adult weight?
From 8 weeks, but treat anything before 12 weeks as a rough guide. Puppies grow in bursts, so a single early weigh-in can mislead. Weigh your puppy at the same time of day each week and run the calculator again at 4 to 5 months, when the range tightens a lot.
Does it work for mixed breeds?
Yes. Leave the breed blank and it works backwards from your puppy's age and weight alone, using the growth patterns of dogs of every size. The range is wider than for a known breed, because the calculator can't see how big the parents were.