BMI Calculator

Calculate your Body Mass Index — metric or imperial.

Your BMI
22.9Normal
1518.5253040

BMI Calculator — What It Does

Enter your height and weight in metric (cm/kg) or imperial (ft/in/lbs) and this calculator instantly computes your Body Mass Index. It displays your BMI value, the corresponding WHO category, and a visual scale showing where you fall on the spectrum.

BMI Categories (Adults 20+)

BMI is a population-level screening statistic, not a personal health diagnosis. Its key limitations:

Limitations of BMI

Frequently Asked Questions

What is BMI and how is it calculated?
BMI (Body Mass Index) is weight in kilograms divided by height in meters squared (kg/m²). In imperial units: (weight in lbs × 703) ÷ height in inches². It's a screening tool, not a diagnostic measure.
What are the BMI categories?
Underweight: below 18.5. Normal weight: 18.5–24.9. Overweight: 25–29.9. Obese Class I: 30–34.9. Obese Class II: 35–39.9. Obese Class III (severe): 40 and above. These apply to adults aged 20+.
Is BMI an accurate measure of health?
BMI is a population-level screening tool with well-known limitations. It cannot distinguish between muscle and fat mass, so athletes often show elevated BMI. It also doesn't account for age, sex, or fat distribution.
What is a healthy BMI for children?
For people under 20, BMI is interpreted using age- and sex-specific percentile charts rather than fixed categories. A BMI at or above the 95th percentile indicates obesity in children.
What should I do if my BMI is outside the normal range?
Consult a healthcare professional for a complete assessment. BMI is just one indicator — a doctor will consider body composition, waist circumference, blood pressure, cholesterol, and other factors together.