Is my cat underweight?

[CarGirl]

When I stroke her you can feel every vertabrae easily, I always feed her when she asks but can't leave a constant supply around as her fatso brother would just eat it.

I know you are supposed to be able to feel the ribs but she is quite boney to stroke IYSWIM!

I've just stroked mine and I can also feel her backbone and she's really fluffy.
You could take her to the vet and have her weighed, they probably wouldn't charge you just for that and would be able to tell you if she's underweight
(they would probably try to book her in for an all over check for 1,000's of pounds though!)

Weigh her yourself, get on the scales to get your weight, then get on again holding moggy then you have her weight! For a full grown cat she should be around 4kg depending on build ofc.

she is quite a petite build, she will probably sit on the kitchen scales long enough for me to weigh her I was told she was 8lbs perhaps I am just used to fat cats!

Why don't you call your vets and see if they have nursing clinics - may be a small fee, may be free depending on your vet. At least then you can get some advice and if there is a concern arrange to see the vet after that.

We have a tiny 9 year old tortie who only weighs just under 3kg. Vets have never commented on her weight, can feel her shoulder blades but not really her vertebrae.