BMI Calculator
About the BMI Calculator
Calculate your Body Mass Index (BMI) from your height and weight, in metric or imperial units. BMI is a quick screening measure used worldwide to classify weight status in adults. The calculation runs entirely in your browser — your height and weight are never uploaded or stored anywhere.
This tool works in your browser: the files and text you use are processed on your device and are not uploaded.
How to use it
- Choose metric (kg/cm) or imperial (lb/ft-in) units.
- Enter your height and weight.
- Read your BMI and its category on the standard WHO scale.
Frequently asked questions
How is BMI calculated?
BMI = weight (kg) ÷ height (m)². In imperial units: BMI = 703 × weight (lb) ÷ height (in)². A 70 kg person at 1.75 m has a BMI of 22.9.
What are the BMI categories?
By WHO classification for adults: under 18.5 is underweight, 18.5–24.9 is a healthy weight, 25–29.9 is overweight, and 30+ is obese. Some Asian populations use lower cut-offs (23 for overweight) because health risks rise at lower BMIs.
Is BMI accurate for everyone?
BMI does not distinguish muscle from fat, so muscular athletes can read as "overweight" while people with low muscle mass can read healthy despite excess body fat. It also is not designed for children, pregnant women, or the elderly. Treat it as a screening signal, not a diagnosis.
What should I do if my BMI is outside the healthy range?
A single number is not a verdict — waist circumference, body composition, blood work, and fitness matter too. Discuss the full picture with a doctor before making major diet or exercise changes.
This tool provides general estimates for informational purposes only and is not medical advice. Always consult a qualified healthcare professional about your health, diet, or pregnancy.