⚖️ BMI Calculator
Body Mass Index is a quick screening number: your weight in kilograms divided by your height in meters squared. It does not measure body fat directly, but across populations it tracks closely enough to flag underweight, healthy weight, overweight and obesity.
Athletes with heavy muscle can score as “overweight” while being very lean, so treat BMI as a starting point — pair it with the body fat calculator for a fuller picture.
How to use this calculator
Type your height in centimetres and your weight in kilograms, then read off your Body Mass Index and the weight category it falls into.
- Enter your Height in the cm field.
- Enter your Weight in the kg field.
- Check the headline BMI number plus the Underweight to Obese category label.
- Compare the reading with the healthy 18.5-24.9 range shown underneath.
Frequently asked questions
What does this BMI calculator actually compute?
It divides your weight in kilograms by your height in metres squared and places the result into standard WHO-style categories: underweight, normal weight, overweight or obese. You only need to supply your height and weight.
Which formula does it use?
The classic Quetelet formula: BMI = weight (kg) / height (m) squared. It then maps the number against the standard cut-offs of 18.5, 25 and 30 for the category label.
Can you show a worked example?
A person 175 cm tall weighing 70 kg has a BMI of 70 divided by 1.75 squared, which comes to 22.9 - comfortably inside the normal weight range. Add 10 kg and the same person would score 26.1, which lands in the overweight band.
How accurate is BMI for me?
BMI is a screening figure, not a diagnosis: muscular athletes and very tall or short people can get misleading readings. Pair it with the body fat calculator on this site, and talk to a clinician before making any big health decisions.