BMI Calculator – Adult Body Mass Index

BMI is a screening number from height and weight. It does not diagnose health on its own and does not account for muscle mass, age or ethnicity.

How to use this calculator

BMI is a screening number from height and weight. It does not diagnose health on its own and does not account for muscle mass, age or ethnicity. Results stay in your browser. They are estimates, not financial, tax or medical advice.

Frequently asked questions

How is BMI calculated?

BMI = weight (kg) / height (m)², with height converted from centimetres.

What categories are shown?

Adult WHO-style bands: underweight below 18.5, normal 18.5–24.9, overweight 25–29.9, obesity 30 and above.