Baby Growth Reference
See how your baby's growth compares.
Weight, length and proportion — with corrected age support for babies born early.
Enter your baby's measurements
DD/MM/YYYY
DD/MM/YYYY
DD/MM/YYYY · This lets the tool calculate corrected age automatically for the age-based WHO reference.
For children under 2, WHO uses recumbent length (measured lying down).
Enter weight, length, or both. Nothing you enter here is sent anywhere; the calculation runs in your browser.
Your baby's growth reference will appear here.
A single percentile is only one point in time. Growth patterns across repeated measurements are usually more useful than one number.
WHO growth reference
Growth reference
Weight vs length
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Enter both measurements
Weight vs age
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Not entered
Length vs age
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Not entered
Weight compared with length
WHO weight-for-length reference · 45–110 cm
The dot is your baby's measurement. The lines show the WHO reference — not targets to follow.
A baby can be higher or lower for both weight and length while still being proportionate. This compares weight with babies of a similar length.
Concerned about a measurement? Your baby's doctor is the right person to interpret growth in context.
Uses official WHO Child Growth Standards for weight-for-age, length-for-age and weight-for-length. For babies born early, age-based results can use corrected age once the expected due date has passed. WHO source · AAP corrected-age guidance.
FOR THEIR AGE
They're changing. What they need is too.
We've already done much of the looking. See the UpBoxes arranged for where they are now.
Choose your UpBox
Choose Mini, Standard or Premium to continue.
0–3 MONTHS
Newborn days.
Choose an UpBox aboveSuggested from age only — never from weight, length, percentile or growth result.
Common questions
- What does a percentile actually mean?
- A percentile compares your baby with the WHO reference group of the same age and sex. At the 40th percentile, 40 out of 100 babies would measure less and 60 would measure more. It is a position on a reference curve, not a score or a target.
- Which WHO reference does this tool use?
- It uses the WHO Child Growth Standards for weight-for-age, length-for-age and weight-for-length, from birth to 24 months, for boys and girls.
- Should I use corrected age if my baby was born early?
- Yes. If you enter a due date, the tool uses corrected age for the WHO comparison, which is the standard approach for babies born preterm.
- Is a low or high percentile a problem?
- Not on its own. Healthy babies grow along many different percentiles. The pattern over several measurements is more useful than any single one. If you are worried, your baby's doctor is the right person to interpret it.
- Is my data stored?
- No. Everything is calculated in your browser. Nothing you enter is sent to us or saved anywhere.
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