How to use
- Enter Baby's sex, Age, Current weight, Current height in Baby BMI & Weight-for-Length Calculator. Use the freshest measurement you have, ideally from the same day or clinic visit.
Baby BMI & Weight-for-Length Calculator
Check your baby's BMI and weight-for-length percentile using CDC/WHO charts.
Result
Your Baby · Baby BMI & Weight-for-Length Calculator
BMI: 16.9 kg/m²
49.5 Percentile
Typical range
Age (months): 12.0 Months
Weight: 9.50 kg (9.5 kg)
Current height: 75.0 cm (75.0 cm)
Z-score: -0.01
Reference: WHO Child Growth Standards (WHO Child Growth Standards (2006)) · Supported ages: 0–60 months
Recommendation
Your baby is growing within the normal range
About baby BMI
BMI-for-age is used by WHO and CDC to assess weight relative to length in infants. The percentile compares your baby's BMI to a reference population of the same age and sex.
Parent guide
How to use this tool
Check your baby's BMI and weight-for-length percentile using CDC/WHO charts.
What the result means
Check your baby's BMI and weight-for-length percentile using CDC/WHO charts.
Method
BMI = kg/m² followed by LMS BMI-for-age percentile
Worked example
Important limitation
BMI-for-age is a screening measure and must be interpreted with growth history and clinical context.
Primary sources
References and data notes
Safety note
Use this result for planning and discussion. Contact a qualified healthcare professional for unusual growth changes, feeding difficulty, fever, missed vaccines, developmental concerns, or urgent symptoms.
Next tools to compare
Baby Weight Percentile CalculatorCalculate your baby's weight percentile using WHO or CDC growth charts. See if your baby is growing on track.Baby Height Percentile CalculatorDetermine your baby's height percentile based on WHO or CDC growth charts. Track your baby's growth.Baby Milk Intake CalculatorEstimate your baby's daily milk intake based on weight and age. Get feeding guidance.
Frequently asked questions
Which sources and method does this tool use?
The method, version and primary sources are listed in the evidence section above.
Why might Baby BMI & Weight-for-Length Calculator differ from a clinic visit?
Home measurements, rounding, age calculation, units, and reference choices can all shift the result. Use the same measurement method over time and bring concerns to your pediatrician.
What should I compare with this result?
Compare it with Baby Weight Percentile Calculator, Baby Height Percentile Calculator, Baby Milk Intake Calculator, recent trends, feeding or sleep notes, and your child's usual behavior. A steady pattern is usually more informative than one isolated value.