Ideal Body Weight page 2

[LauraSB]

125 is probably achievable for a woman your height. It's hard to say if you could carry enough muscle mass to look muscular at that weight. Is that really what you want, or are you thinking more of the smooth, slightly bony look of a Victoria's Secret model? For an idea of what different amounts of muscle look like on a woman about your size, check out Meet Staci: Your New Powerlifting Super Hero | Nerd Fitness

You know, I love my scale. I get on that baby every single morning. But when I look in the mirror, I can see very clearly that just losing what looks like 10 lbs of fat around my middle is not going to give me a body that looks amazing in a swim suit. And losing another 10 lbs beyond that isn't going to do it either. The only thing that's going to give me the look I want is some serious strength training. And that's going to add pounds, not remove them. So if you want a muscular body, I think you need to love the mirror more than the scale.

[Graycat]

I haven't weighed myself in a long time. The last time I did I was 122lbs. As long as I'm not feeling up any love handles, my thighs don't have too much of a jiggle when I move them and my waist is still reasonably narrow, I'm okay. And clothes, jeans mostly are a great gauge for measuring BF.

[Kochin]

125 is probably achievable for a woman your height. It's hard to say if you could carry enough muscle mass to look muscular at that weight. Is that really what you want, or are you thinking more of the smooth, slightly bony look of a Victoria's Secret model? For an idea of what different amounts of muscle look like on a woman about your size, check out Meet Staci: Your New Powerlifting Super Hero | Nerd Fitness

I'm her height and 125 for me would probably be achievable, but "ribs showing territory".
I know what you're getting at, but remember that different bone-structures and base muscle-levels can shift things around a lot. We'd have to see her or an approximation of her body-shape to get an idea of how small/light she can get and still be healthy. And I'd say 125 might be pushing it.
Then again: weight is weight. Body fat would still be a more reasonable measurement.