A normal body mass index is considered to be between 18.5-24.9 For example, if you are 5'6", a healthy weight is anywhere between 118-155.
One cannot calculate the BMI with weight alone as the height is also needed. To calculate the BMI that way you take your weight in kilograms and divide it by the square of your height in meters.
Height and diameter will give you the volume, if you know the density you can then calculate weight from that.
apex:WeightHeight
The best way to accurately calculate your weight would be to weight yourself in the morning. I would also look up calculate myweight.com and put your weight and height they will tell you what you should be.
Height & weight.
To calculate the weight: Height x Width x Length x 2.5
Multiply its weight by its height.
Height and weight.
If you are an adult and in between the height of 4.8 and 5.4 then you are.
It is not possible to calculate weight just from length, width and/or height. (These can give you volume and area, but not weight). For weight, you need to know "how heavy it is per this amount of stuff" is - e.g "3 grams per square cm" or "6 tonnes per inch".
A person's weight and height.
You need your age, height and weight to calculate it. I linked an article in the "Related Links" section that explains what BMR is and how it effects your weight. It also, of course, explains how to calculate it.