Body Mass Index (BMI) Calculator
Give it your height and weight in metric or US units and you'll get a general adult BMI, the category it lands in, and the healthy-weight range for your height, with a simple gauge to picture it. Treat it as a screening estimate rather than a diagnosis — and nothing you enter is saved.
- 100% free
- Private & safe
- Runs in your browser
Why use BMI Calculator?
BMI Calculator gives a quick, private estimate using well-established formulas — informational only, and nothing you enter is stored.
- Runs instantly in your browser — nothing to install, nothing uploaded.
- Completely free, with no account, no watermarks and no usage limits.
- Handles Metric: BMI = kg / m²; US: BMI = 703 × lb / in².
- Choose metric (kg, cm) or US customary (lb, ft, in).
- Works on any device — desktop, tablet and phone — and is fully keyboard accessible.
What it can do — and its limits
- Calculates Body Mass Index from weight and height in metric or US units.
- Shows your healthy-weight range and where your BMI falls.
- An adult screening estimate — not a medical diagnosis.
How to use BMI Calculator
- Choose metric (kg, cm) or US customary (lb, ft, in).
- Enter your weight and height.
- See your BMI, its general adult category and the healthy-weight range for your height.
- A visual gauge places your result on the standard scale.
Examples
- A 70 kg person at 175 cm has a BMI of about 22.9 (healthy range).
- Checking the healthy-weight window for a given height.
Worked example
Input
70 kg, 175 cm.
Output
BMI 22.9 — within the healthy range (18.5–24.9).
Supported formats & limits
- Metric: BMI = kg / m²
- US: BMI = 703 × lb / in²
WHO adult BMI categories
| Category | BMI range |
|---|---|
| Underweight | below 18.5 |
| Healthy | 18.5 – 24.9 |
| Overweight | 25 – 29.9 |
| Obese | 30 and above |
Limitations
- BMI is a screening tool, not a diagnosis, and does not measure body composition.
- It may not suit children, pregnancy, older adults or very muscular individuals.
Common problems & fixes
Athletic build flagged 'overweight'.
BMI can't tell muscle from fat; treat it as a rough screen, not a verdict.
Frequently asked questions
Is BMI a medical diagnosis?
No. It is a general adult screening estimate. For health decisions, consult a qualified professional.
Do you save my weight and height?
No. Everything is calculated in your browser and nothing is stored or uploaded.
Does BMI apply to athletes or children?
BMI is a general adult screening estimate and may misclassify very muscular people, children, pregnancy and older adults.