BMI calculator
Nothing you type leaves this device.
The short answer
BMI is your weight in kilograms divided by the square of your height in metres. At 175 cm and 70 kg it comes out at 22.9, which counts as a healthy weight. That is 5 ft 9 in and 154 lb, and the tool takes either.
Your height and weight stay in this tab. They are health data, and health data is exactly the kind of thing that should not be posted to a server to divide two numbers.
The formula
BMI = kg ÷ m²
Worked examples
- 70 kg at 175 cm
- 22.9 — a healthy weight
- 95 kg at 180 cm
- 29.3 — overweight
- 52 kg at 168 cm
- 18.4 — underweight
Reference table
| BMI | Category | At 175 cm (5 ft 9 in), that is | The same weight in pounds |
|---|---|---|---|
| Under 18.5 | Underweight | under 57 kg | under 125 lb |
| 18.5 to 25 | A healthy weight | 57 kg to 77 kg | 125 lb to 169 lb |
| 25 to 30 | Overweight | 77 kg to 92 kg | 169 lb to 203 lb |
| 30 to 40 | Obese | 92 kg to 123 kg | 203 lb to 270 lb |
How to use it
- 01Enter your weight and heightWeight in kilograms, pounds or stones; height in centimetres or feet and inches. Each field has its own unit, so kilograms with feet is fine.
- 02Read the figure and the bandThe number is pinned at the bottom with the band it falls in as its caption, and the scale above shows how close you are to the next band.
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Searches that land here include bmi calculator, body mass index, healthy weight range, bmi chart adults, bmi calculator in feet and inches and bmi calculator with pounds and stones.
About BMI
What it does and does not measure
BMI is weight divided by height squared. That is the whole of it. It was devised to describe populations, not individuals, and it cannot tell muscle from fat or say where on a body the weight sits. A rugby forward and a sedentary person of the same build can return the same figure. It is a useful first screen and a poor last word.
Questions people ask
Is this accurate for children?
No. Children are assessed against age-and-sex percentile charts rather than the adult bands, because a growing body changes ratio constantly. Ask a GP or practice nurse rather than a calculator.