Health Calculators
BMI Calculator
Body Mass Index (BMI) is a widely used screening measure that relates your weight to your height. Enter your height and weight — in metric or imperial units — t
Private by design: this tool runs 100% in your browser. Nothing you enter is sent, stored, or tracked.
How to use this calculator
- Choose metric (kg, cm) or imperial (lb, ft/in).
- Enter your height and weight.
- Your BMI and category appear instantly.
The formula
BMI = weight (kg) ÷ height (m)². In imperial: BMI = 703 × weight (lb) ÷ height (in)². Standard adult categories: under 18.5 underweight, 18.5–24.9 healthy, 25–29.9 overweight, 30+ obesity.
Worked example
A person who is 175 cm (1.75 m) and 70 kg: BMI = 70 ÷ (1.75 × 1.75) = 22.9 — in the healthy range.
About this tool
Body Mass Index (BMI) is a widely used screening measure that relates your weight to your height. Enter your height and weight — in metric or imperial units — to get your BMI and its standard category instantly.
Frequently asked questions
Is BMI accurate?
BMI is a screening tool, not a diagnosis. It doesn't distinguish muscle from fat, so athletes may score high while being lean, and it doesn't account for age, sex, or body composition. Treat it as one data point.
Does BMI work for children or athletes?
Children and teens use BMI-for-age percentiles, not adult cutoffs. Very muscular people, older adults, and pregnant people should interpret results cautiously or use other measures.
What should I do about my result?
If your BMI is outside the healthy range and you're concerned, talk to a healthcare professional. This calculator provides information only — not medical advice.
Is my health data private?
Completely. The calculation happens in your browser; your height and weight are never sent, stored, or logged anywhere.