BMI calculator
Calculate your Body Mass Index from height and weight. Shows BMI category, healthy weight range and contextual guidance for adults.
- Free, no sign-up
- No data stored
- Reviewed 2026-01-15
Your details
Results
- Category
- Bmi category severe underweight
- Healthy range
- 805.8 lb – 1,084.6 lb
- BMI prime
- 0.07
- Ponderal index
- 0.4
- To gain
- 730.8 lb
Bmi prime note
Ponderal note
- Bmi category mild underweight
- Bmi category normal
- Bmi category overweight
- Bmi category obese 1
- Bmi category obese 2+
WHO classification
| Bmi range | Category | |
|---|---|---|
| 16 | Bmi category severe underweight | ← |
| 16 – 17 | Bmi category moderate underweight | |
| 17 – 18.5 | Bmi category mild underweight | |
| 18.5 – 25 | Bmi category normal | |
| 25 – 30 | Bmi category overweight | |
| 30 – 35 | Bmi category obese 1 | |
| 35 – 40 | Bmi category obese 2 | |
| 40+ | Bmi category obese 3 |
Who note
Bmi limits note
About the BMI Calculator
Body Mass Index is a simple screening measure that relates weight to height. Enter your height and weight in metric or imperial units to see your BMI value and where it falls on the WHO classification scale.
The calculator also shows the healthy weight range for your height, and notes that BMI does not distinguish between muscle and fat. Athletes or muscular individuals may show a high BMI without excess body fat.
BMI is not a diagnostic tool. It does not account for age, sex, ethnicity or body composition. Use it as a starting point, not a conclusion.
How to use the BMI Calculator
- Select metric or imperial units.
- Enter your height.
- Enter your weight.
- Optionally add age and sex for additional context.
- View your BMI, category and healthy range.
Formula and method
BMI = weight (kg) / height (m)2
Frequently asked questions
What is a healthy BMI?
The WHO classifies 18.5–24.9 as normal weight. Below 18.5 is underweight; 25–29.9 is overweight; 30+ is obese.
Is BMI accurate for athletes?
Not always. Muscle weighs more than fat, so muscular people may have a high BMI without excess body fat. Consider body fat percentage for a fuller picture.
Does BMI apply to children?
Children use age- and sex-specific percentile charts rather than fixed thresholds. This calculator is designed for adults (18+).
Are there ethnic variations?
Yes. Some populations (e.g. South Asian) have higher health risks at lower BMI values. The WHO suggests lower thresholds for certain ethnic groups.
Sources
Figures are estimates for guidance only. Always confirm with the official source or a qualified professional before acting on them.