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Body mass index (BMI) calculator
BMI compares weight and height. It is a quick guide, not a measure of your worth: below we explain how to read it and when it can mislead.
How to read your result
BMI is weight in kilograms divided by height in metres squared. The World Health Organization uses these ranges: under 18.5 below the healthy range, 18.5 to 24.9 healthy, 25 to 29.9 above, 30 and over well above.
When BMI misleads
- Muscular people can have a high BMI with little fat.
- With age we lose muscle, so a normal BMI can hide extra fat.
- The scale does not suit pregnancy, teenagers or professional athletes.
That is why BMI works best alongside your waist measurement and how you feel. For women a waist over 80 cm is a reason to look more closely at food and movement.
Be kind to yourself
A number on a screen says nothing about your worth or beauty. If thoughts about weight make you anxious, talking to a professional helps more than a strict diet.
This calculator is for information only and does not replace medical advice.