About this tool
Body Mass Index (BMI) is a simple screening measure that relates your weight to your height. It's widely used by health organizations as a quick, population-level indicator, though it doesn't account for muscle mass, body composition, age, or sex. Enter your height and weight in either metric or imperial units to get your BMI and category instantly.
How to use it
- 1Choose metric (centimeters and kilograms) or imperial (feet, inches, and pounds) units.
- 2Enter your height and weight.
- 3Your BMI and weight category update automatically as you type.
- 4Compare your result against the standard BMI category chart shown below the result.
Common mistakes to avoid
- Treating BMI as a diagnosis rather than a screening tool — it doesn't distinguish muscle from fat.
- Using outdated height or weight measurements instead of current ones.
- Applying adult BMI categories to children or teenagers, who need age- and sex-specific growth charts instead.
- Ignoring that BMI ranges can differ slightly by ethnicity and are less reliable for very muscular individuals.
Use cases
- Getting a quick general sense of whether your weight falls in a typical healthy range for your height.
- Tracking BMI changes over time alongside a fitness or nutrition plan.
- Preparing for a doctor's visit where BMI is commonly discussed.
Frequently asked questions
What is a healthy BMI range?
For most adults, a BMI between 18.5 and 24.9 is considered a healthy weight range, according to the World Health Organization's standard classification.
Is BMI accurate for athletes or very muscular people?
Not always. Because BMI only uses height and weight, it can classify muscular individuals as "overweight" even when their body fat percentage is low. It's best used as one data point, not a complete picture.
How is BMI calculated?
Metric: weight in kilograms divided by height in meters squared. Imperial: (weight in pounds × 703) divided by height in inches squared.