BMI Calculator

Weight kg

Height cm

Result

BMI22.724403
CategoryNormal

This result is informational only and is not professional advice.

A population statistic applied to one person

Calculate body mass index from height and weight, with the WHO categories and an honest explanation of where BMI stops being useful.

BMI is weight divided by height squared. It was designed in the 1830s to describe populations, and it does that job well — it was never intended to assess an individual.

The formula cannot distinguish muscle from fat, or where fat sits. A muscular athlete and someone carrying excess weight can share a BMI of 27 while being in entirely different health situations.

What this calculator shows

Your BMI value and its WHO category
The weight range that would place you in the healthy band
Both metric and imperial input

What to keep in mind

Standard categories: under 18.5 underweight, 18.5–24.9 healthy, 25–29.9 overweight, 30+ obese.
These cut-offs were derived from European populations; risk thresholds differ for South and East Asian groups.

FAQs

Is BMI accurate for athletes?

Often not. Muscle is denser than fat, so many athletes register as overweight or obese while carrying very little body fat.

What is a healthy BMI?

18.5 to 24.9 by WHO criteria. Waist circumference and waist-to-height ratio predict metabolic risk better for most individuals.

Why does BMI use height squared?

It was an empirical fit for adult populations. It systematically overestimates for tall people and underestimates for short ones, since bodies do not scale in two dimensions.

Does BMI apply to children?

Not directly. Children are assessed on age- and sex-specific percentile charts, because body composition changes constantly during growth.

Worked example

A worked case

Input: 180 cm, 81 kg

Output: BMI 25.0

Note: That lands one decimal into 'overweight'. For a lean, muscular person it may mean nothing at all — which is precisely the limitation of the measure.

Useful links

All tools in Health calculators for weight, lab values and training

BMI Calculator

Result

Related tools

When can I drive after drinking?

Daily Calorie Intake Calculator

BMR Calculator

Useful links