BMI Calculator for Adults (Metric and Imperial)
Adult BMI with WHO category, in kg/cm or lb/ft/in.
BMI is a screening measure, not a diagnosis. It doesn't tell muscle from fat, and these categories are for adults only, not children or teenagers (who are assessed with age- and sex-specific charts) or pregnancy. Talk to a health professional about your weight and health.
Use via API
Adult body mass index with the WHO category and the healthy weight range for the height, in metric or imperial units. Send JSON, get JSON back.
POST https://pithlab.com/api/v1/tools/bmi-calculator
curl https://pithlab.com/api/v1/tools/bmi-calculator \
-H "Authorization: Bearer $PITHLAB_KEY" \
-H "Content-Type: application/json" \
-d '{"units":"metric","weight":70,"height":175}'About the BMI Calculator
Calculate adult body mass index from height and weight in metric or imperial units, with the WHO category and the weight range for a normal BMI.
How to use the BMI Calculator
- Choose metric (kg and cm) or imperial (lb, feet and inches).
- Enter your weight and height.
- Read your BMI, the WHO adult category and the weight range that gives a BMI of 18.5 to 24.9 at your height.
Examples
Input
70 kg, 175 cm
Output
BMI 22.9: Normal weight (WHO adult range 18.5 – 24.9)
Input
200 lb, 5 ft 10 in
Output
BMI 28.7: Pre-obesity (overweight) (WHO adult range 25.0 – 29.9)
Frequently asked questions
How is BMI calculated?
BMI is weight in kilograms divided by height in metres squared. 70 kg at 1.75 m is 70 ÷ 1.75² = 22.9. Imperial values are converted to metric first.
Is BMI a diagnosis?
No. BMI is a quick screening measure. It doesn't distinguish muscle from fat or show where fat is carried, so a very muscular person can score as overweight. Talk to a health professional about what your result means for you.
Can I use this for children or teenagers?
No. These categories are for adults aged 18 and over. Children and teenagers are assessed with age- and sex-specific BMI charts (percentiles), not adult cut-offs.
Are the cut-offs the same for everyone?
These are the WHO adult categories. Some health bodies recommend lower thresholds for certain ethnic groups, such as people of South Asian descent, and BMI is not meant for use during pregnancy.