BMI Calculator
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Results
Your BMI
24.4
CategoryNormal weight
Healthy Weight Min128.9 lbs
Healthy Weight Max173.6 lbs
Body mass index
- 1.Convert height to metres
The index is defined in kilograms per square metre, so centimetres have to go first.
- 2.Square the height
Squaring rather than cubing is a deliberate approximation: body mass grows faster than height but slower than volume would suggest. It is also the index's main known weakness — it systematically reads high for tall people and low for short ones.
- 3.Divide mass by squared height
The result is a mass per unit area — a single number comparable across body sizes.
Adolphe Quetelet proposed weight divided by height squared while studying the statistical distribution of human measurements — he was describing populations, not diagnosing individuals. Ancel Keys coined the name 'body mass index' 137 years later, and noted in the same paper that it was only adequate as a population measure.