For a 5'0" height, 128lbs is considered overweight (above 25 BMI) and 154lbs is considered obese (above 30 BMI). 94lbs and below is considered underweight (below 18.5 BMI). Keep in mind also that the BMI system does not account for body fat percentage.
Source: BMI Calculator.
115 lbs.
125
120lbs
287 pounds!
5kg
About 80 pounds
125-135lbs
90 pounds
65-80 pounds
45-55 kilos
It really varies on how muscly you are or what your natural shape is but it is on average 8.8stone.
This average would be distorted, as there are so many overweight people, but the healthy weight for a girl of 5 foot would be between 90 to 110 pounds