BMI Calculator for Kids

Free BMI calculator for children and teens. Estimate BMI with age-aware guidance notes.

Metric: enter height in centimetres (e.g. 170).

How to Use

  1. Select your preferred units for weight (kg or lbs) and height (cm or ft/in).
  2. Enter your weight and height.
  3. Click Calculate to see your BMI, category, and position on the BMI scale.

Understanding BMI

Body Mass Index (BMI) is a screening tool that estimates body fat using height and weight. Categories: Underweight (<18.5), Normal (18.5–24.9), Overweight (25–29.9), and Obese (30+).

BMI is a starting point — not a diagnosis. Talk to a healthcare professional for personalized advice.

Frequently Asked Questions

What is a healthy BMI?
A BMI between 18.5 and 24.9 is generally considered normal for most adults. Individual health also depends on muscle mass, age, and other factors.
How is BMI calculated?
BMI = weight (kg) ÷ height (m)². For imperial units, the calculator converts pounds and feet/inches automatically.
Is BMI accurate for athletes?
BMI does not distinguish muscle from fat, so muscular people may show a higher BMI without excess body fat. Consider body fat percentage for more detail.
Can I use this BMI calculator for kids?
This tool shows the standard adult BMI formula. For children and teens, BMI-for-age percentiles from a pediatrician are more appropriate.

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