BMI Body Mass Index
US (Imperial Units) Online Calculator 
This calculator provides calculation of BMI (Body Mass Index) in US imperial (ft, in, lb) or metric units (m, kg).
BMI Category
Chart / Table
BMI ( body mass index ) Category Chart / Table: 
Severely underweight
less than 16.5
BMI
Underweight body
from 16.5 to 18.4
BMI
Normal
body from 18.5 to 24.9
BMI
Overweight
body from 25 to 30 BMI
Obesity (Class I)
from 30.1 to 34.9
BMI
Obesity (Class II)
from 35 to 40
BMI
Obesity (Class III)
over 40
BMI 
Example BMI for a person with height = 5 ft 3 inch : 
92 lb at 5′3″ = 16.30 BMI
100 lb at 5′3″ = 17.71 BMI
120 lb at 5′3″ = 21.25 BMI
160 lb at 5′3″ = 28.34 BMI
190 lb at 5′3″ = 33.65 BMI
220 lb at 5′3″ = 38.97 BMI
260 lb at 5′3″ = 46.05 BMI

Body mass index (BMI) is a body weight (in kg) divided by the square of his height (in meters, metric) and measured in kg/m2. There is a corrective coefficient 703 used In order to calculate the index in imperial units (inches and pounds). BMI is used to find a normal person's body weight (so called healthy weight) based on a person's height. BMI is a measurement which estimates a proportion of person's weight and height. Body mass index is often used as diagnostic index to identify if individual is obese, overweight, normal or underweight. BMI (also called Quetelet index) was invented by Adolphe Quetelet (a Belgian scientist and mathematician) in 19th century (between years 1830 and 1850).
Sample conversion: Somebody has weight 160 pounds and is 5 ft 3 inch tall  the BMI is going to be 28.34 after the calculator is used (Overweight body according the reference table). 
