Kitten Growth & Weight
'Is my kitten the right size?' is one of the most common worries new owners have. The short answer: British Shorthairs grow slowly and keep going for a long time, and a steady upward trend matters much more than hitting an exact number.
Rough weights by age
These are typical ranges for healthy British Shorthairs. Males are usually at the top end and females at the bottom, and individual cats vary a lot.
- 8 weeks: 0.8–1.2 kg (1.8–2.6 lb)
- 12–13 weeks (going-home age): 1.2–1.8 kg (2.6–4 lb)
- 6 months: 2.3–3.5 kg (5–7.7 lb)
- 1 year: females 3–4 kg (6.6–8.8 lb), males 4–5.5 kg (8.8–12 lb)
- Fully grown (around 3 years): females 3–5.5 kg (7–12 lb), males 4–8 kg (9–17 lb)
They fill out late
British Shorthairs often look leggy and gangly at 6–12 months, then spend the next two years broadening out: chest, cheeks and (in unneutered males) jowls. A one-year-old that looks 'too skinny for a British Shorthair' is usually just a teenager.
Tracking it
Weigh your kitten every week or two: a kitchen scale works for small kittens. Once they're bigger, weigh yourself holding the cat and then subtract your own weight. Write it down. A kitten that keeps gaining steadily is doing fine. One that stops gaining or loses weight should see the vet.
Big or overweight?
A heavy adult isn't always a big one. The scale can't tell you whether that 7 kg is frame or fat, but your hands can (see Feeding & Portions).