BMI Calculator

BMI Formula & Categories

Body Mass Index (BMI) = weight (kg) ÷ height (m)². In US units it is 703 × weight (lb) ÷ height (in)².

WHO BMI Categories (Adults)

BMI does not distinguish muscle from fat and is not suitable for athletes or pregnant women. Results are for reference only — consult a doctor for health concerns.

Frequently Asked Questions

What is a healthy BMI?

By the WHO standard, a BMI of 18.5–24.9 is normal, below 18.5 is underweight, 25–29.9 is overweight, and 30 or above is obese.

How is BMI calculated?

BMI = weight (kg) ÷ height (m)². In US units, BMI = 703 × weight (lb) ÷ height (in)². For example, 160 lb at 5′9″ (69 in) gives a BMI of about 23.6.

Is BMI accurate?

BMI does not distinguish muscle from fat, so it can be misleading for athletes, pregnant women and the elderly. Use it as a general screening tool and consider body-fat percentage too.

What is my healthy weight range?

Healthy weight = BMI 18.5–24.9 × height (m)². For example, at 5′9″ (1.75 m) a healthy weight is about 126–168 lb (57–76 kg).