Child Growth Calculator

How to Use the Child Growth Calculator

Enter your child's age (in years or months), select their sex, and enter their height in centimetres and weight in kilograms. The calculator will show a BMI figure (for children 2 years and older) and a general guidance note using simplified reference ranges.

How to Measure Height and Weight Correctly

For height: stand the child against a flat wall without shoes, use a flat book placed on top of the head, and measure from the floor to the underside of the book. For weight: use consistent scales, ideally in the morning before breakfast, with light clothing.

What Affects a Child's Growth

A child's growth is influenced by genetics, nutrition, sleep quality, physical activity, and general health. Illness or periods of stress can temporarily affect growth patterns. Short-term variations are normal — consistent patterns over months are more informative than a single measurement.

Growth Patterns by Age

• 0–2 years: Rapid growth. Weight and length are tracked against WHO growth charts.
• 2–5 years: Growth slows but remains steady. BMI-for-age tracking begins.
• 5–10 years: Gradual, consistent growth. Activity and nutrition have growing importance.
• 11–18 years: Puberty introduces significant growth spurts. Timings vary widely between children.

When Parents Should Ask a Pediatrician

Speak to your child's doctor if you notice your child has stopped growing for several months, is significantly smaller or larger than peers of the same age, or if you have any concerns about their development, appetite or energy levels. Growth concerns are always best assessed in person.

Why One Result Does Not Define a Child's Health

Growth is a journey, not a snapshot. A single measurement — even from a clinical setting — tells only part of the story. What matters is the pattern of growth over time. Children naturally vary widely in size and develop at their own pace.