When do Siamese cats reach full size?

Most Siamese cats reach their adult body weight by around 12 months of age. Some males may continue to develop muscle mass through 18 months. The breed's typical adult weight is 2.5–4.5 kg (5.5–10 lb), with males generally toward the upper end of that range.

How much should a Siamese kitten weigh at 3 months?

At 3 months, a Siamese kitten typically weighs approximately 1.2–1.6 kg (2.6–3.5 lb). Individual variation based on sex, litter size, and genetics is normal. The most important indicator is consistent week-over-week weight gain rather than a specific number.

Is it normal for a Siamese kitten to look very thin?

Yes — the lean, angular Siamese build means kittens often look slender, especially between 4 and 9 months when height growth outpaces muscle development. As long as the kitten is gaining weight consistently, eating well, and active, this is normal for the breed. If you are concerned, your vet can assess body condition objectively.

Siamese Growth Chart: What to Expect | PetCalculator

Siamese kittens grow quickly but stay lean — here's what normal growth looks like from birth through adulthood, and how to tell if your kitten is on track.