Calculate body mass index and the WHO adult category
Enter weight and height in US or metric units. Get the BMI and where it sits in the WHO adult classification.
BMI is weight in kilograms divided by the square of height in meters. The calculator assigns categories from the WHO adult classification.
Body mass index
26.5 kg/m²
Pre-obesity
| Underweight | Below 18.5 |
|---|---|
| Normal weight | 18.5 to 24.9 |
| Pre-obesity | 25.0 to 29.9 |
| Obesity class I | 30.0 to 34.9 |
| Obesity class II | 35.0 to 39.9 |
| Obesity class III | 40 or above |
A screening measure for adults. It does not measure body fat or its distribution.
How it works
Understand the result
Use BMI as a screening measure
BMI relates weight to height. It does not measure body fat, muscle or where fat is carried, so use it as a starting point.
Apply the categories to adults only
Children and adolescents need age and sex specific growth charts. Some guidance also uses lower cut-offs for people of Asian background.
Enter US or metric units
The calculator converts pounds to kilograms and feet and inches to meters before it divides, so both give the same result.
Use the result to support your judgment
A calculator gives a number from the inputs you type. It knows nothing else about the patient, and it does not replace clinical judgment or local guidance.
In a workup
Keep the measurement with its source
Add the weight and height to the patient's notes in Workup Desk. When you draft an assessment, it picks up the figures under examination findings, and you can ask the record when they were last measured.
See asking the recordQuestions
Frequently asked questions
Why does a muscular patient show as overweight?
Muscle is dense. BMI cannot tell muscle from fat, so it can overstate fat in athletes and understate it in older adults.
Which WHO terms does the calculator use?
Underweight, normal weight, pre-obesity and obesity classes I, II and III, with the WHO cut-offs at 18.5, 25, 30, 35 and 40.
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