Calculators
BMI Calculator
Enter your height and weight to see your BMI, category, position on the scale, and healthy weight range. Works in metric or imperial units.
BMI is a general indicator. Consult a doctor for medical advice.
How BMI is calculated
Body Mass Index estimates whether your weight is in a healthy range for your height. It does not measure body fat directly, so it works best as a quick screening guide rather than a diagnosis.
BMI = weight (kg) / height (m)2Imperial: BMI = 703 × weight (lb) / height (in)2BMI does not tell muscle from fat, so very muscular people can read as overweight. It also ignores age, sex, bone structure, and where fat is carried, so read it alongside other health markers rather than on its own.
BMI categories
The standard adult BMI categories used by health organizations worldwide.
| Category | BMI range |
|---|---|
| Underweight | Below 18.5 |
| Normal weight | 18.5 to 24.9 |
| Overweight | 25 to 29.9 |
| Obese | 30 and above |
Frequently asked questions
Is BMI accurate for everyone?
BMI is a useful screening tool for populations but not a personal diagnosis. It can misjudge very muscular or very lean people because it only uses height and weight, not actual body composition.
Why might an athlete have a high BMI?
Muscle is denser than fat, so a muscular athlete can weigh more for their height and read as overweight or obese on BMI even with low body fat. A body fat measurement is more useful in that case.
What is a healthy BMI range?
For most adults a BMI between 18.5 and 24.9 is considered healthy. The best point within that range varies from person to person and depends on other health factors.
Does BMI work for children?
Not in the same way. Children and teenagers use age and sex specific BMI percentiles rather than the fixed adult categories, so use a pediatric chart for anyone under 18.
Should I worry if my BMI is slightly outside the normal range?
A single reading is only one indicator. Trends over time, waist measurement, diet, activity, and advice from a doctor matter far more than a number just above or below a cutoff.