BMI Calculator

Work out your Body Mass Index (BMI) from your height and weight, and see which weight category it falls into.

How this calculator works

BMI is calculated by dividing weight by the square of height. It's a quick screening tool, not a diagnosis — it doesn't distinguish muscle from fat.

BMI = weight(kg) / height(m)²
Imperial inputs are converted to metric automatically before calculating.

How to interpret your BMI

Under 18.5 is considered underweight, 18.5–24.9 is considered a healthy range, 25–29.9 is considered overweight, and 30 or above is considered obese, according to standard adult BMI categories.

BMI doesn't account for muscle mass, bone density, or body composition, so athletes and very muscular people often score higher than their actual body fat would suggest.

Frequently asked questions

Is BMI accurate for everyone?

BMI is a useful screening tool for most adults but can be misleading for athletes, older adults, and people with unusually high or low muscle mass. It doesn't measure body fat directly.

What is a healthy BMI range?

For most adults, a BMI between 18.5 and 24.9 is considered a healthy weight range.

Does BMI differ for men and women?

The standard BMI formula is the same for adult men and women, though body composition differences mean it's interpreted somewhat differently in clinical practice.