Metric: 80 kg at 180 cm
- Input
- Weight = 80 kg, Height = 180 cm (1.80 m)
- Working
- BMI = 80 ÷ 1.80^2 = 80 ÷ 3.24 = 24.69, shown as 24.7.
- Result
- BMI = 24.7
BMI Calculator
Calculate body mass index from weight and height using the WHO formula, in metric or imperial, and locate the result in the published WHO bands. Runs entirely in your browser — your numbers never leave this device.
Units
Body mass index (BMI)
24.7
WHO band: Normal weight
- Weight range for BMI 18.5–24.9
- 59.9 – 80.7 kg
- Height
- 180 cm
- Weight
- 80 kg
Informational only. This calculator applies a published formula to the numbers you enter — it is not medical advice, a diagnosis, or a substitute for a clinician. Talk to a qualified professional about decisions concerning your health.
How it works
BMI = weight (kg) ÷ height (m)^2 (WHO definition) | Imperial form: BMI = 703 × weight (lb) ÷ height (in)^2
| Band | BMI range |
|---|---|
| Underweight | Below 18.5 |
| Normal weight | 18.5 – 24.9 |
| Overweight | 25.0 – 29.9 |
| Obesity | 30.0 and above |
Body mass index is the index the World Health Organization publishes for classifying weight relative to height. It is a single division: weight in kilograms divided by height in metres squared. The imperial form multiplies pounds by 703 and divides by height in inches squared — the 703 is the unit-conversion constant that makes the two forms agree, not a separate formula.
The WHO publishes bands for the index: below 18.5, 18.5–24.9, 25.0–29.9, and 30.0 and above. Those bands are printed in the table on this page as published facts, so a calculated value can be located against them directly. The index itself is a population-level screening number: it uses only weight and height, and it does not distinguish between mass from muscle, bone or fat, which is why other tools in this category — body fat, lean body mass and body surface area — exist alongside it.
This calculator computes the index and nothing more. It does not interpret a result for a person, and it is informational only. All calculation runs in the browser; weight and height are never uploaded or stored.
Worked examples
Imperial: 180 lb at 70 in
- Input
- Weight = 180 lb, Height = 70 in
- Working
- BMI = 703 × 180 ÷ 70^2 = 126,540 ÷ 4,900 = 25.82, shown as 25.8.
- Result
- BMI = 25.8
Metric: 95 kg at 170 cm
- Input
- Weight = 95 kg, Height = 170 cm (1.70 m)
- Working
- BMI = 95 ÷ 1.70^2 = 95 ÷ 2.89 = 32.87, shown as 32.9.
- Result
- BMI = 32.9
Frequently asked questions
Which formula does this calculator use?
The WHO form: weight in kilograms divided by height in metres squared. Imperial entries are converted with the equivalent form, 703 × pounds ÷ inches squared, which returns the same index.
Where do the BMI bands come from?
They are the bands published by the World Health Organization: below 18.5, 18.5–24.9, 25.0–29.9, and 30.0 and above. They are printed on this page as a reference table so a result can be located against the published scale.
Does BMI measure body fat?
No. BMI is calculated from weight and height only. It does not measure fat, muscle or bone separately. The Body Fat Calculator and Lean Body Mass Calculator in this category estimate composition by different published methods.
Is this medical advice?
No. This page computes an index from a published formula for information only. It does not diagnose, interpret a result for a person, or advise on any decision. Questions about health belong with a clinician who knows the full picture.
Are weight and height stored?
No. The calculation runs entirely in the browser. Measurements are never uploaded, stored or tracked — closing the tab removes them.
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