To answer the question
What weight would I need to be to be 'x' BMI (Body Mass Index)
We have created a reverse BMI (Body Mass Index) calculator to help you discover what weight you would need to be in order to reach your target BMI, this will help with goal setting. It's fine to know you need to have a BMI of 25 and under to be within the under weight category, but what weight is that for you! Well simply add your target BMI and your height below and this handy calculator will give you a weight range that you would need to be to reach that BMI.
Read more about BMI here - BMI (Body Mass Index)