How big will your kitten get?

How a kitten grows

Very fast and fairly predictably. It is born weighing about a hundred grams, doubles its weight in the first week and, from then on, a healthy kitten gains roughly half a kilo (about a pound) a month until five or six months. At around six months it has about two thirds of its final weight, and most cats reach their adult weight at around one year. That is why its weight today and its age give a fairly good estimate of what it will weigh as an adult.

The breeds that take years

The large ones, such as the Maine Coon, the Norwegian Forest Cat, the Siberian, the Ragdoll or the Savannah, keep growing and gaining muscle until three or four. A one-year-old male Maine Coon can weigh six kilos and end up at nine. If you choose one of these breeds, the tool uses a slower curve, and it is worth asking your vet how long to keep it on kitten food, which is often longer than a year.

Sex matters more than size

In cats, the difference between a male and a female from the same litter is often bigger than the difference between two medium-sized breeds: a male often ends up one or two kilos heavier than his sister. That is why breed profiles give the weight as a range from female to male, and why this tool lets you enter the sex. A European Shorthair or an ordinary moggy usually ends up between three and a half and five and a half kilos.

What to watch for

That it gains weight every week. With kittens, kitchen scales are the best tool: if it stops gaining or loses weight, even while eating, it is time for the vet, because at that age everything moves fast. And after neutering, watch out for the other extreme: appetite goes up and energy use goes down, so that is exactly when the extra kilos begin. Adjusting its food at that point prevents most obese two-year-old cats.