What is body mass index (BMI)?

Body mass index (BMI) is a value derived from the mass (weight) and height of a person. The BMI is defined as the body mass divided by the square of the body height, and is expressed in units of kg/m2, resulting from mass in kilograms and height in metres.

What is a BMI Calculator?

It is a type of calculator that measures body fat based on weight and height applied to men and women. All you require is to insert the body weight and height using standard or metric measures. On clicking the calculate button, you’ll get your BMI in relevant selected units — US units or Metric units.

Kilograms and Meters (or centimeters)
Formula: weight (kg) / [height (m)] ²
Since you normally measure height in centimeters, but for the formula, we need it in meters. We have to convert in meters first. There’s no rocket science; just divide centimeters by 100 to get height in meters. Example: Weight = 50 kg, Height = 155 cm (1.55 m) Calculation: 50 ÷ (1.55) ² = 20.81

Pounds and Inches
If you’ve weight measured in kilograms, that`s great, but in the case of pounds, we need to make some amendments in the formula. We have to multiple by a conversion factor of 703 to get BMI, when weight is in pounds and height in inches.

Example: Weight = 160 lbs, Height = 5’10″ (70″)
Calculation: [160 ÷ (70) ²] x 703 = 22.95

What is the Metric Version of BMI Calculator?

In the metric BMI calculator formula for BMI weight is measured in kilograms and height in meters squared rather than inches. Since the alternative units are used, this calculator is named the metric BMI calculator. Under this process where you want to use height in centimeters, the formula includes weight in kg divided by height in centimeters squared, multiplied by 10,000 to get the results.

BMI table for adults

Category	BMI range - kg/m2
Severe Thinness	< 16
Moderate Thinness	16 - 17
Mild Thinness	17 - 18.5
Normal	18.5 - 25
Overweight	25 - 30
Obese Class I	30 - 35
Obese Class II	35 - 40
Obese Class III	> 40