Formosan Mountain Dog Weight & Size
How big does a Formosan Mountain Dog get?
A full-grown Formosan Mountain Dog is a medium dog, weighing about 26–40 lb as an adult.
- Adult weight
- 26–40 lb
- Also in kilograms
- 12–18 kg
- Size class
- Medium
Formosan Mountain Dog Size
As a medium breed, a Formosan Mountain Dog reaches its adult weight earlier than a large dog — smaller breeds finish growing sooner (Hawthorne et al., 2004).
Formosan Mountain Dog Growth Chart
What a Formosan Mountain Dog puppy weighs week by week, from the growth curve FEDIAF publishes (Nutritional Guidelines 2025, Table VII-8a) for a dog whose expected adult weight is 15.0 kg. It is an average, not a target, and it is only valid from 8 weeks to one year — FEDIAF notes that growth patterns show a certain individual variability. Read a row as the middle of a spread.
| Age | Weight | % of adult weight |
|---|---|---|
| 8 weeks | 9 lb (4.3 kg) | 28% |
| 10 weeks | 12 lb (5.5 kg) | 37% |
| 12 weeks | 14 lb (6.5 kg) | 43% |
| 14 weeks | 16 lb (7.4 kg) | 49% |
| 16 weeks | 18 lb (8.1 kg) | 54% |
| 18 weeks | 19 lb (8.7 kg) | 58% |
| 20 weeks | 21 lb (9.3 kg) | 62% |
| 24 weeks | 23 lb (10.3 kg) | 69% |
| 28 weeks | 25 lb (11.2 kg) | 75% |
| 32 weeks | 26 lb (11.9 kg) | 80% |
| 36 weeks | 28 lb (12.6 kg) | 84% |
| 40 weeks | 29 lb (13.2 kg) | 88% |
| 44 weeks | 30 lb (13.7 kg) | 91% |
| 48 weeks | 31 lb (14.2 kg) | 94% |
| 52 weeks | 32 lb (14.6 kg) | 97% |
Common questions
How much does a full-grown Formosan Mountain Dog weigh?
A Formosan Mountain Dog weighs 26–40 lb (12–18 kg) as an adult. That range is the mass Wikidata publishes for the breed under a CC0 license, re-checked here every week — it is a typical weight across many adult dogs, not a target for one dog.
Is a Formosan Mountain Dog a medium dog?
Yes — a Formosan Mountain Dog counts as a medium breed, going by the middle of its adult weight range (12–18 kg). The cut-offs between small, medium, large and giant are a common veterinary convention rather than one official standard, so a breed near a boundary can be described either way elsewhere.
When does a Formosan Mountain Dog stop growing?
Earlier than a large dog. Hawthorne et al. (2004) measured that smaller breeds finish growing sooner, so a Formosan Mountain Dog reaches something close to its adult weight before a big breed would. We don't publish a month-by-month figure, because no source gives one breed by breed — and an invented number would be worse than none.
Why is there a range instead of one weight?
Because the source publishes a range. Within any breed, weight varies with sex, genetics, build and health, and a mixed-breed dog usually falls between its parents' breeds. Narrowing 26–40 lb down to a single number would look more precise while being less true.
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Weight varies within the Formosan Mountain Dog by sex, genetics and health, and mixed-breed dogs fall between their parents. This is a typical range, not a guarantee.
Verified on . Based on Wikidata — dog breed mass (property P2067) (Wikimedia Foundation, query run 2026-07-22, CC0 license), Body-Weight Changes during Growth in Puppies of Different Breeds (Hawthorne et al., Journal of Nutrition, 2004, vol. 134, p. 2027S) and Nutritional Guidelines for Complete and Complementary Pet Food for Cats and Dogs (FEDIAF (European Pet Food Industry Federation), 2025 edition (growth curves Table VII-8a, growth energy VII-8b and VII-10)). See the method.