BMI calculator

How to use

Body mass index divides weight by height squared. It is a screening number, not a diagnosis: it places a person in a broad weight band so that a conversation about health can start, and it says nothing about body composition, muscle or fat distribution.

• Get a quick reference of your weight band.
• Track the direction of a change over months, using the same method.
• Understand a BMI value quoted by a health app or report.

1. Enter your weight in kilograms.
2. Enter your height in centimetres — the calculator converts it to metres.
3. The result gives the index and the corresponding band.

Formula

BMI = weight ÷ (height in metres)²

Example

70 kg at 1.75 m gives 70 ÷ 3.0625 = 22.9, inside the normal band (18.5 to 24.9).

Limitations

• Athletes with a lot of muscle often land in the overweight band without excess fat.
• The index was not designed for children, adolescents, pregnant people or the very elderly.
• The bands are a statistical reference; only a professional can interpret them for one person.

Frequently asked questions