About the Puppy Weight Calculator
Puppy Weight Calculator estimates how heavy your puppy will be when it is fully grown. Enter the puppy's weight now and its age in weeks, in pounds or kilograms, and say whether you expect a small, medium or large breed. The page uses two common rules of thumb: the age ratio rule (weight now divided by age in weeks, times 52) and, at about six months, the share of adult weight that a puppy of that size usually has reached. It shows the estimate with a likely range and a note on when your puppy will stop growing. It is a guess, since breed, genes and food all matter.
Updated October 2026
How to use the Puppy Weight Calculator
- 1Enter the puppy's weight now and choose pounds or kilograms.
- 2Choose its age in weeks.
- 3Choose the expected adult size: small, medium or large.
- 4Read the estimated adult weight and range.
- 5Check with your vet, who can compare it with the breed's growth chart.
Rules of thumb
Puppies grow in a predictable curve, fast at first and then more slowly. The age ratio rule assumes that growth by week stays roughly the same, which works best between about 14 and 20 weeks. At six months most medium and large puppies have reached around 55% to 65% of their final weight, and small breeds about 75%.
What changes the answer
Breed is the biggest factor, then the size of the parents, food and health. A puppy that has been ill or underfed may be smaller for a while and catch up later. Neutering early can change growth plates in large breeds, so ask your vet about timing.
- Breed and parents' size
- Quality and amount of food
- Health and parasites
- Timing of neutering
Growth and feeding
Feed a food made for puppies of your puppy's expected adult size, because large-breed puppies need a controlled energy level and calcium to protect their joints. Use the Dog Calorie Calculator for the amount, and weigh your puppy weekly to see the trend.
Related tools
Plan the food with the Dog Calorie Calculator, work out your dog's age with the Pet Age Calculator, choose a name with the Pet Name Generator and convert weights with the Weight Converter.
Features
- Age ratio rule from 10 to 40 weeks
- Six-month rule for each size
- Likely range
- Pounds and kilograms
- Growth notes by size
- Private: nothing is uploaded
Frequently asked questions
How do I estimate my puppy's adult weight?
One rule is to divide the weight by the age in weeks and multiply by 52. Another is to double the weight at about 14 weeks for a medium dog. The calculator uses the ratio rule and a six-month rule.
How accurate is it?
Roughly within 10% to 15% for many puppies, and less accurate for mixed breeds. Genes, food and health change the result.
When does my puppy stop growing?
Small dogs finish at 6 to 9 months, medium dogs at about a year and large or giant breeds at 18 to 24 months.
Does it work for a mixed breed?
It gives a rough estimate. For a mix, use the size of the larger parent breed and ask your vet, who may estimate from the paws and bone structure.
Does a puppy's paw size tell me anything?
Big paws can suggest a bigger dog, but it is not reliable on its own.
When do I weigh my puppy?
Weigh at the same time of day, once a week, and write it down. A steady upward curve is what you want.
Should my puppy be fat or thin?
Neither. You should be able to feel the ribs and see a waist. Overweight puppies risk joint problems, especially large breeds.
Is this veterinary advice?
No. It is a rough estimate. If you are worried about your puppy's growth, ask your vet.