BMI Calculator
Enter your height and weight to calculate your Body Mass Index, see which category it falls into, and find a healthy weight range for your height.
Your calculation is performed in your browser.This result is an estimate for informational and educational purposes. It isn’t a diagnosis and isn’t a substitute for advice from a doctor, registered dietitian, or other qualified professional. See our methodology and sources for the formula used and its limitations.
How it works
BMI is calculated by dividing your weight in kilograms by the square of your height in metres. The result is compared against standard World Health Organization thresholds to place it into an underweight, normal weight, overweight, or obesity category.
Formula & methodology
BMI compares your weight with your height squared. Height is converted to metres and weight to kilograms first, so metric and imperial inputs give the same result. BMI is a screening measure and does not distinguish muscle from fat.
BMI = weight (kg) ÷ height (m)²BMI = 703 × weight (lb) ÷ height (in)²What each term means
- Weight
- Body weight in kilograms (or pounds).
- Height
- Standing height in metres (or inches).
BMI categories
| BMI | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Normal weight |
| 25.0 – 29.9 | Overweight |
| 30.0 and above | Obesity |
Worked example
A person who is 175 cm tall and weighs 70 kg has a BMI of 22.9, which falls in the normal weight range.
Common uses
- —Getting a quick screening estimate of whether your weight is in a typical healthy range for your height.
- —Tracking BMI over time alongside a weight loss or gain goal.
- —Preparing for a medical appointment or health screening that asks for your BMI.
Important notes
- —BMI is a screening tool, not a diagnosis — it does not directly measure body fat and can be less accurate for athletes, older adults, or during pregnancy.
- —Use the Body Fat Calculator and Ideal Weight Calculator alongside BMI for a fuller picture.