BMI Calculator

Check your Body Mass Index (BMI) to know about your body health condition, whether you are underweight, over weight or obese.

According to WHO and U.S.National Institute of Health, the BMI ranges for adults 20 years and older are,

  • A BMI below 18.5 is considered underweight.
  • A BMI of 18.5 to 24.9 is considered healthy.
  • A BMI of 30 or higher is considered obese.

How to calculate BMI

Should you wish to calculate your BMI manually, I’ve included some simple instructions and formulae below. It’s important that if you use these, you ensure that your units are in the same unit system (metric or imperial) and the correct corresponding unit.

To work out your BMI (kg and m)

  1. Divide your weight (kg) by your height (m).
    Example: 65kg ÷ 1.83m = 35.519
  2. Divide your answer from part 1 by your height again.
    Example: 35.519 ÷ 1.83 = 19.41

To work out your BMI (pounds and inches)

  1. Divide your weight (lb) by your height (in).
    Example: 154lb ÷ 71in = 2.169
  2. Divide your answer from part 1 by your height again.
    Example: 2.169 ÷ 71 = 0.03055
  3. Multiply your answer from part 2 by 703.
    Example: 0.03055 × 703 = 21.48

BMI formula

The official formula for BMI was devised in the 1830s by Belgian mathematician Adolphe Quetelet.

Metric BMI Formula
BMI = weight (kg) / height2 (m2)

Imperial BMI Formula
BMI = ( weight (lb) / height2 (in2) ) x 703