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Baby growth percentile calculator
Enter your baby's birth date and any of weight, length or head size. The percentile shows as you type.
WHO Child Growth Standards, birth to 24 months. Sources read on 5 Nov 2026.
Your baby
What the percentile means
The 40th percentile for weight means about 40 in 100 babies of the same age and sex weigh less, and 60 weigh more. Any percentile can be healthy. What doctors watch is whether your baby keeps roughly to the same curve from visit to visit.
Your Child Health Booklet uses Singapore's own charts
The growth charts printed in the Health Booklet come from a Singapore study: the National Healthcare Group Polyclinics' Anthropometric Study on Pre-School Children, 2000. HPB publishes them only as drawn curves, with no numbers we could build a calculator on. HealthHub's digital booklet also grades readings "based on our local growth charts".
This calculator uses the World Health Organization's Child Growth Standards instead. The Singapore Medical Journal (2016) names WHO charts alongside Singapore's as the ones to use, so a reading here can land a few percentile points away from the dot in your booklet.
Where the numbers come from
| What | Source | Read |
|---|---|---|
| Percentiles, 0 to 24 months | WHO Child Growth Standards: L, M and S values by month for weight-for-age, length-for-age and head circumference-for-age, boys and girls. We checked them against WHO's printed tables: at 12 months, boys' weight runs from 7.8 kg (3rd) to 11.8 kg (97th). | 5 Nov 2026 |
| Charts in the Health Booklet | HPB Health Booklet: 0 to 72 month charts from the NHG Polyclinics study, 2000; 4 to 18 year charts from HPB's school children study, 2002. | 5 Nov 2026 |
Age is counted in months of 30.4375 days, the way WHO counts it, and values between whole months are interpolated.
Questions parents ask
What is a normal percentile for a baby?
Any percentile can be normal. The booklet's charts draw lines from the 3rd to the 97th percentile. Doctors look at whether a baby keeps to roughly the same curve over several visits, not at one reading.
Which growth chart does the Singapore Health Booklet use?
Singapore's own: the 0 to 72 month charts come from the NHG Polyclinics Anthropometric Study on Pre-School Children (2000), and the school-age charts from HPB's 2002 study of school children. HPB publishes them as drawings only, so this tool uses the WHO standards, which the Singapore Medical Journal also names.
Can I use it after 2 years?
No. The WHO tables here stop at 24 months. From age 6, HPB publishes BMI-for-age cut-offs, which our kids BMI calculator uses.
Sources
- WHO Child Growth Standards: weight-for-age (read 5 Nov 2026)
- WHO Child Growth Standards: length/height-for-age (read 5 Nov 2026)
- WHO Child Growth Standards: head circumference-for-age (read 5 Nov 2026)
- HPB Health Booklet (2014 edition, PDF on HealthHub) (read 5 Nov 2026)
- HealthHub: Children's health e-services (digital health booklet) (read 5 Nov 2026)
- Goh LH. Failure to thrive in babies and toddlers. Singapore Med J 2016;57(6):287-291 (read 5 Nov 2026)
