What is the right weight for someone at 5'7?

Anwhere in the healthy range is great!

Depends on your personal style... gym bunnies at the top end... fashionistas at the lower end...

What would you say would be a good weight for me to be?

I think it depends on your frame, your muscles, etc.. I remember a long time ago someone saying if you are 5 feet tall you should be 100 pounds, and add 5 pounds for every inch That's obviously not a scientific measurement!

I don't think anyone can tell you, you'll just know when you get there.

you're right, and it's not only not scientific, it's a potentially dangerous target for all women who have average or larger than average frames. It's a good target for small framed women only.

body fat percentage is much better, i.e. get it measured reliably and base your goal weight on that, while losing fat slowly to make sure it's just fat you're losing and not muscle: http://www.leighpeele.com/body-fat-pictures-and-percentages

That makes the target for a woman of 5'7" 135. That is not "potentially dangerous" no matter what your "frame," It's pretty spot on healthy.

really, it's healthy? I'm 5'1", 130lb, and my lean body mass is 101 lb, please explain to me how I could possibly be healthy at 105lb?

2% body fat is unattainable for anyone, even male bodybuilders on steroids can't get below 3% body fat. Essential body fat in women is 12-13%. The only way I can get to 105lb is by starving off about 20lb of lean body mass. If my lean body mass was 81lb, then I could be 105lb at a healthy body fat percentage. But how is it possibly healthy for me to starve off 20lb of lean body mass?

Explanation: your calculations are wrong. AND it's quite easy to lose lean body mass where that lbm is the result of intentionally putting it on.

YEP, calculations are wrong

MOST 5'0 women look FINE and are perfectly healthy at 100 lbs... in fact thats a BMI of 19.5 which is SMACK DAB IN THE MIDDLE of the acceptable range... a 5'0" woman could go as low as 95 pounds and NOT be underweight

at 5'1, 130 lbs, BMI is 24.6 which is pretty close to being overweight....
now BMI is not the end all, be all...HOWEVER I find it hard to believe that someone at 5'1 has 101 lbs of lean body mass.... those calculations mentioned above are dead wrong

You find it hard to believe.... are you a doctor? an anthropologist? Have you studied variation in humans? do you have statistics to back that up? (and 19.something BMI is right at the low end of the BMI range, not smack bang in the middle... the middle of the BMI range for 5'1 is 116lb)

I've studied biology, anthropology and palaeoanthropology. My frame size is at the high end of the normal range for modern humans, and all my data above is within the normal range. Yes I'm at the high end of the normal range for LBM/frame size for height, but I'm not a freak of nature - there is a lot of variation in humans.

I also have a much larger rib cage than average for my height, and a much greater lung capacity than average for my height, and I also have short, wide hands and feet to the point that I can't buy shoes from normal shoe shops. They're short and wide like the rest of me. I don't call myself "neandermagnon" for no reason. (neanderthals were short and large framed, with big rib cages, wide shoulders, short and wide hands and feet, etc, and they had relatively short forearms/shins compared to upper arms/femurs, which is true about me as well, so that effectively subtracts about 2 inches from my height without affecting my weight much, compared to if I had average limb proportions, i.e. longer shins but the rest of me the same)

BTW since I wrote my earlier posts, I've done a bulk (i.e. eating and training for strength/lean mass gains).... I'm now 140lb in weight, and my lean body mass is somewhere between 102 and 107lb, depending on how my body fat percentage is measured. Most of that would be noob gains (this is my first time doing training and eating like this), I'm not expecting my lean body mass to go up by much more in the future (although if it does I won't complain)

And the reason why I'm still making this point (yeah I know it's a really old post I made months ago) is because I'm not a freak of nature, there are other large framed people out there, who don't want to be trying to weigh 105lb at 5'1" tall, and a lot of people don't realise that until they've actually lost too much weight, or got an eating disorder or something. Oh yeah, on that, as a teenager I nearly got an eating disorder because of an idiot sports coach with a BMI chart who told me to lose 10kg (22lb) when I had visible upper abs, which means I probably had a body fat percentage as low as 18%, but I was right at the top of the BMI chart for my height then as well. I know there are people who kid themselves that they're large framed/big boned/whatever because they don't want to admit that they're obese, but there are also people who *really are* large framed and should not try to get to "one size fits all" kinds of goal weights.

And it works the other way, I have a friend who has a tiny frame and she's underweight on BMI, but she's the right weight for her frame size, and she lifts weights and eats loads, and her doctor has said she's the right weight for her frame size.... yet people have told her that she has an eating disorder, is mentally ill, and even that will die if she doesn't gain weight, based on BMI. Which is kind of rude really. Any "one size fits all" goal weight, that says there's only one "right" weight for anyone of any given height, should be avoided like the plague. Instead, go by body fat percentage.