BMI Calculator
Calculate your adult Body Mass Index, understand the result, and see the healthy-weight range for your height.
Check your BMI
Enter your height and weight. Your information is private.
Your result
Enter your measurements to calculate your BMI.
What this result means
Body Mass Index is a screening measure, not a diagnosis.
Save your result
Copy your BMI summary or download it as an image or PDF.
Adult BMI categories
The highlighted row updates after you calculate your result.
| Category | BMI range |
|---|---|
| Underweight | Below 18.5 |
| Healthy weight | 18.5–24.9 |
| Overweight | 25.0–29.9 |
| Class 1 obesity | 30.0–34.9 |
| Class 2 obesity | 35.0–39.9 |
| Class 3 obesity | 40.0 or higher |
About the BMI Calculator
Body Mass Index compares your weight with the square of your height. It is commonly used as a quick screening measure for adults, but it cannot describe your complete health or directly measure body fat.
How BMI is calculated
For metric measurements, BMI equals weight in kilograms divided by height in meters squared. For imperial measurements, the result uses pounds and inches with the standard conversion factor.
What the extra results show
- Healthy-weight range: the weights that correspond to an adult BMI from 18.5 through 24.9 at your height.
- BMI Prime: your BMI divided by 25. A value of 1 represents the upper boundary of the standard healthy-weight category.
- Ponderal Index: another height-and-weight ratio that uses height cubed instead of height squared.
Important limitations
BMI does not distinguish muscle from fat, show where body fat is stored, or account for pregnancy and every individual difference. Athletes, older adults, and people with unusual body composition may need additional measurements and professional interpretation.
Privacy
Your measurements are processed only inside your browser. Toolslight does not send, save, or log the height, weight, or BMI you enter here.
Health note: This calculator provides general educational information and is not medical advice or a diagnosis. Speak with a qualified healthcare professional for personal guidance.