Enter your puppy or kitten's current age and weight to get an estimated adult weight range and full maturity timeline.
🐾 Enter Your Pet's Details
Select the expected adult size category for your breed
🎯 Estimated Adult Weight
Maturity Age
Growth Stage
Growth Progress
BirthFull Adult
⚠️ This is an estimate. Genetics, nutrition, and health affect actual adult size. Consult your vet for a personalised assessment.
Dog Breed Size Reference
Size
Adult Weight
Full Maturity
Examples
🐕 Toy
<4 kg (<9 lbs)
8–10 months
Chihuahua, Pomeranian, Yorkshire Terrier
🐕 Small
4–10 kg (9–22 lbs)
10–12 months
Beagle, Pug, Shih Tzu
🐕 Medium
10–25 kg (22–55 lbs)
12–15 months
Border Collie, Cocker Spaniel, Bulldog
🐕 Large
25–45 kg (55–99 lbs)
18–24 months
Labrador, Golden Retriever, Husky
🐕 Giant
>45 kg (>99 lbs)
18–30 months
Great Dane, Mastiff, Saint Bernard
🐈 Cat
3.5–6 kg (8–13 lbs)
12 months (most breeds)
Maine Coon/Ragdoll up to 3–4 years
How the Formula Works
For puppies: The tool uses the Brody formula as a base — Adult Weight ≈ (Current Weight ÷ Age in weeks) × Maturity weeks — adjusted by breed size. Toy breeds are assigned a shorter maturity window; Giant breeds a longer one, improving accuracy.
For kittens: The formula is Adult Weight ≈ (Current Weight ÷ Age in weeks) × 52 for kittens under 20 weeks. This gives a reliable estimate for typical domestic cats.
Always verify with a vet. Spay/neuter status, diet quality, and underlying health conditions can significantly affect growth trajectories.
💬 Frequently Asked Questions
The most reliable method is the weight-at-age formula: Adult Weight ≈ (Current Weight ÷ Age in weeks) × Maturity weeks. Small breeds mature around week 40; large breeds around week 80. This calculator automatically selects the right window based on your chosen breed size.
Most domestic cats reach their full adult weight by 12 months. Large breeds like Maine Coon and Ragdoll may continue growing until 3–4 years. This calculator uses 52 weeks as the standard maturity point, which covers the vast majority of breeds.
It provides a science-based estimate derived from veterinary growth formulas. Accuracy is highest when the pet is still actively growing (under 50% of their maturity age). Results are less reliable for older pets nearing or past maturity.