Baby Growth Percentile Calculator
Weight, length and BMI percentiles from birth to 2 years. Free, private and instant.
How to use the Baby Growth Percentile
- Pick metric (cm, kg) or imperial (ft, in, lb) units.
- Choose baby is a: Boy or Girl.
- Enter age in years and months.
- Enter weight.
- Enter length.
- Press Calculate to get an instant result with a colour scale, chart and plain-English explanation.
About the Baby Growth Percentile
See where your baby sits compared with other babies of the same age and sex. This calculator gives percentiles for weight, length and BMI from birth to 24 months using WHO-based reference data, with growth curve charts that show your baby’s position.
Also known as: baby percentile calculator, infant growth chart, WHO baby growth chart, baby weight percentile.
Worked example
- Baby is a: Boy
- Age: 1 year
- Weight: 9.6 kg
- Length: 75.7 cm
Baby weight-for-age percentile: 50th percentile (BMI-for-age: Healthy weight). At 1 year: weight 50th, height 50th, BMI 50th percentile. Weight is in the "typical" range.
- Weight percentile: 50th
- Height percentile: 50th
- BMI: 16.8
- BMI-for-age percentile: 50th
Formula and cut-offs
Weight and BMI use a log-normal z-score, length uses a normal z-score, against approximate WHO growth standard medians for age and sex. Percentile = standard normal CDF of the z-score.
Frequently asked questions
What is a good percentile for a baby?
Any value between about the 3rd and 97th percentile is normal. Following their own curve matters more than the number.
Why is my baby on a low percentile?
Genetics, prematurity and feeding patterns all play a part. See your doctor if growth drops across percentile lines.
Should I use WHO or CDC charts?
The WHO charts are recommended for babies under 2 years in most countries.
What is the baby weight-for-age percentile for a 1-year-old boy, 9.6 kg and 75.7 cm?
Baby weight-for-age percentile: 50th percentile (BMI-for-age: Healthy weight). At 1 year: weight 50th, height 50th, BMI 50th percentile. Weight is in the "typical" range. Enter your own numbers above for a personal result.
Sources and references
Written and checked by the MediHub editorial team against the sources above. Read how we build and review our calculators.
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Last updated . This calculator is for education only and is not medical advice. See the medical disclaimer.