Use this BMI calculator to estimate your Body Mass Index from your height and weight and see how the result compares with commonly used adult BMI categories.
Estimate Body Mass Index from height and weight.
What Is BMI?
Body Mass Index (BMI) is a screening measure that relates body weight to height. It is widely used to group adult weight status into categories, but it does not directly measure body fat or overall health.
BMI Formula
Metric: BMI = weight (kg) ÷ height² (m²).
US units: BMI = 703 × weight (lb) ÷ height² (in²).
How to Use the BMI Calculator
- Select Metric or US / Imperial units.
- Enter your height and weight.
- Select Calculate to see your estimated BMI and category.
Understanding Your BMI Result
| BMI | Adult category |
|---|---|
| Below 18.5 | Underweight |
| 18.5–24.9 | Healthy weight |
| 25.0–29.9 | Overweight |
| 30.0 or above | Obesity |
Example Calculation
A person who weighs 80 kg and is 1.75 m tall has an estimated BMI of 80 ÷ (1.75 × 1.75) = 26.1.
Limitations of BMI
BMI does not distinguish fat mass from muscle mass and may not reflect body composition equally well for every person. It should be interpreted together with other health information rather than used as a diagnosis.
Related Calculators
Frequently Asked Questions
Is BMI the same as body fat percentage?
No. BMI uses only height and weight, while body fat percentage estimates how much of body weight is fat.
Can athletes have a high BMI?
Yes. People with high muscle mass can have a higher BMI even when body fat is not high.
Is BMI a medical diagnosis?
No. BMI is a screening measure and should not be used by itself to diagnose a health condition.
Methodology & References
BMI = weight (kg) ÷ height² (m²).