BMI Calculator
Estimate your Body Mass Index from your height and weight, and see which category it falls into.
What is BMI?
Body Mass Index (BMI) is a simple screening measure that estimates whether your weight is in a healthy range for your height. It's widely used by doctors and health organizations as a quick, first-pass check — not a diagnosis — because it can be calculated instantly from just two numbers, without any special equipment.
How BMI is calculated
BMI is your weight in kilograms divided by the square of your height in meters:
BMI = weight (kg) ÷ height (m)²
If you use US units, this calculator converts pounds to kilograms and feet/inches to centimeters first, then applies the same formula — so the result is identical either way.
How to use this calculator
Choose Metric or US units, enter your current height and weight, and press Calculate BMI. You'll get your BMI score, its category, and a table showing where the standard adult BMI ranges fall so you can see how close you are to the next category.
Understanding the categories
Adult BMI is generally grouped into four bands: under 18.5 is considered underweight, 18.5–24.9 is considered a normal weight, 25–29.9 is considered overweight, and 30 or above is considered obese. These thresholds come from World Health Organization guidance and are the same ones used in the results table above.
Limitations of BMI
BMI doesn't distinguish between muscle and fat, so athletes and very muscular people can score as "overweight" despite having low body fat. It also doesn't account for age, sex, bone density, or where fat is distributed on the body. Treat it as a general starting point rather than a precise health verdict — see the Disclaimer for more detail, and pair it with other tools like the TDEE Calculator for a fuller picture of your energy needs.