French Baguette Tools
BMI Calculator
Enter weight and height: the index and its band appear straight away.
The BMI calculator is a free tool that runs entirely in your browser, with no data ever sent to a server. Work out the body mass index and place the result on the scale.
How the index is worked out
Body mass index divides weight in kilos by the square of height in metres. Someone weighing 70 kg at 1.75 m gets 70 ÷ (1.75 × 1.75), which is 22.9. The formula comes from the statistician Adolphe Quetelet in the 19th century: it was designed to describe populations, not individuals.
Reading the bands
The World Health Organization uses: below 18.5 for underweight, 18.5 to 24.9 for a normal range, 25 to 29.9 for overweight, and 30 and above for obesity, itself split into three degrees. Those thresholds were established on adult populations of European descent.
What the index cannot see
BMI ignores body composition. A heavily built rugby player often passes 30 with no excess fat, while a sedentary person can stay under 25 with a high fat mass. Waist circumference tells you far more about abdominal fat, the kind that matters most for cardiovascular risk.
What this tool does not do
This tool makes no diagnosis and does not replace medical advice. It does not suit children and teenagers, who need specific growth charts, nor pregnant women. A result that worries you deserves a conversation with a doctor.
Frequently asked questions
Does a high BMI mean I am in poor health?
Not necessarily. The index measures a ratio between weight and height, nothing more. It is one signal among several, alongside waist size, blood pressure, physical activity and blood work.
Do the same thresholds apply worldwide?
No. Several Asian countries use lower thresholds, since metabolic risk appears there at a lower index. The values shown here are the World Health Organization ones for the general adult population.
Is my data sent to a server?
No: the text you type or paste is processed entirely in your browser, on your device. It is never transmitted to a server.
Do I need an account or an install?
No: the tool works directly on this page, with no sign-up and no installation.