1. What is Children's BMI?

BMI (Body Mass Index) for children is calculated the same way as for adults, but is interpreted differently by comparing to age and gender specific percentiles. The UK NHS uses BMI centile charts to assess healthy weight in children aged 2-18.

2. How the Calculator Works

The calculator uses the standard BMI formula:

The result is then compared to UK NHS growth charts to determine the child's percentile for their age and gender.

3. Understanding BMI Percentiles

Interpretation:

• Below 2nd percentile: Underweight
• 2nd to 91st percentile: Healthy weight
• 91st to 98th percentile: Overweight
• Above 98th percentile: Very overweight (obese)

4. Using the Calculator

Tips: Measure height without shoes and weight in light clothing. Use metric measurements (kg and meters) for most accurate results.

5. Frequently Asked Questions

Q1: Why use percentiles for children?
A: Children's body composition changes with age, so percentiles account for normal growth patterns.

Q2: What if my child is above the 91st percentile?
A: Consult your GP or health visitor for advice. They may suggest lifestyle changes.

Q3: Is BMI accurate for very muscular children?
A: BMI doesn't distinguish between muscle and fat, so athletic children may appear overweight when they're not.

Q4: How often should I check my child's BMI?
A: Routine measurements at school or doctor visits are sufficient unless there are specific concerns.

Q5: Where can I see the full UK NHS growth charts?
A: The complete charts are available on the NHS website and in the Red Book given at birth.