It depends what breed. Some cats are just smaller than others. I have a 9 lb cat who is 7 years old and a 17lb cat who is 6. The smaller one is a domestic shorthair (unknown mix) and the bigger one is half Maine coon.

 

Billi is a DSH. I know kittens have growth spurts, but since he hasn't put on any weight for 5 months, I'm wondering if he's done growing. Sounds like your DSH is similar in size, so I guess it's normal. If he were heavier, I'd need utility cart to bring him to the vet.

 

I have only raised a few kittens, but in my limited experience, they generally do most of their growing up to 9 mos of age. At that point, the skeletal structure seems to have acquired just about all of its adult size, but the kitten may continue to put on muscle mass for up to another 6-18 mos, depending on breed, gender, and genetics.

 

Our ferals stopped full growth at about 1.5 years old. Agreed that genetics, breed, etc. play a big role. The girl grew in length and the boys in bulk...but at about 1 year, you pretty much knew what they would end up looking like.

 

Great! Thanks, guys. I had ordered a small sized soft carrier (up to 10lbs) and wondered if they'd outgrow it. Sounds like they will be ok. Even if one gets a little fatter (or muscular), I do have another carrier that's more spacious.