GWN Tools · Calculators

BMI Calculator

Q: How is BMI calculated?

BMI = weight in kilograms divided by height in metres squared (kg/m²). For imperial units, multiply by 703: BMI = 703 × weight in pounds ÷ height in inches squared.

Q: What are the BMI weight categories?

Under 18.5 is underweight, 18.5 to 24.9 is normal weight, 25 to 29.9 is overweight, and 30 or above is obese.

Q: Is BMI an accurate measure of health?

BMI is a quick screening tool, not a diagnosis. It does not account for muscle mass, age, sex, or body composition, so a muscular person can read as overweight. Treat it as informational only and consult a healthcare professional for medical advice.

Enter your height and weight to find your Body Mass Index and weight category. Switch between metric and imperial units.

Height

Weight

0.0

—

your body mass index

Underweight

< 18.5

Normal

18.5–24.9

Overweight

25–29.9

Obese

≥ 30

Informational only — not medical advice. BMI does not account for muscle mass, age, or body composition.

About the BMI calculator

What is a BMI calculator? A BMI calculator estimates your Body Mass Index from your height and weight and tells you which weight category that falls into.

How is BMI calculated?

BMI = weight in kilograms divided by height in metres squared (kg/m²). For imperial units, multiply by 703: BMI = 703 × weight in pounds ÷ height in inches squared.

What are the BMI weight categories?

Under 18.5 is underweight, 18.5 to 24.9 is normal weight, 25 to 29.9 is overweight, and 30 or above is obese.

Is BMI an accurate measure of health?

BMI is a quick screening tool, not a diagnosis. It does not account for muscle mass, age, sex, or body composition, so a muscular person can read as overweight. Treat it as informational only and consult a healthcare professional for medical advice.