What is a growth percentile, and what does your baby's number mean?

A growth percentile shows how your baby's weight, length or head size compares with other children of the same age. HealthHub gives an example: if your child's height is at the 75th percentile, your child is as tall as or taller than 75% of children that age. On its own the number describes size only, and doctors care most about whether your baby keeps to a similar curve over time.

How to read a percentile on the growth chart

Picture 100 babies of the same age lined up from smallest to biggest, and the percentile is roughly your baby's place in that line. HealthHub puts it this way: a height at the 10th percentile means your child is as tall as or taller than only 10% of children in the same age group. Weight and head size are read the same way.

A low number is not a bad result and a high one is not a good one. NUH says children whose height sits between the 3rd and 97th percentile and who keep a steady growth rate are usually growing normally, especially when that fits the parents' height.

It also helps to compare weight with height. HealthHub says that if both percentiles are about the same and the parents are tall, a bigger child is likely just following the family's genes. A weight percentile far above the height percentile, such as height at the 75th and weight at the 95th, suggests a child is heavy for their height.

Why the trend matters more than one reading

One measurement on its own says little. The NHS says a baby's weight may go up or down by one centile line, but it is less common to cross two, and it suggests talking to a nurse if that happens. It also says weight gain can slow while a baby is ill and usually gets back to normal within 2 to 3 weeks.

Early weeks have their own rules. The NHS says it is normal for babies to lose some weight in the first few days, and most are back at or above their birth weight by 3 weeks. It is also normal for weight and length to sit on different percentiles, though the two are usually fairly similar.

Growth checks at the polyclinic

Your baby's weight, length and head size are plotted in the Child Health Booklet. KKH says the booklet records growth and development along with birth details and vaccinations, and asks you to bring it to every doctor's visit. NUH lists the well-baby visits where growth is checked: shortly after discharge for jaundice, then at 2 weeks, 6 weeks to 2 months, 4, 6, 12 and 18 months.

HealthHub's Children's Health e-service works as a digital companion to the booklet. It grades each reading against Singapore's local growth charts and flags readings in the low or high range so you can ask your doctor or nurse.

Want a number between visits? Our baby growth percentile calculator uses the WHO Child Growth Standards, so it can land a few points away from the local chart in your booklet.

When a percentile is worth a question

Ask at your next polyclinic visit, or sooner, if:

• your baby's weight has dropped across two centile lines, which the NHS says is less common
• your baby is not back to birth weight by about 3 weeks
• HealthHub's app flags a reading in the low or high range
• weight and length percentiles are far apart

KKH lists poor weight gain and poor growth as conditions for your family doctor or polyclinic, not the emergency department, unless your baby is also unwell. If your baby was born small, read low birth weight too.

Frequently asked questions

What is a good percentile for a baby?

There is no best one. NUH says a height between the 3rd and 97th percentile, with a steady growth rate, is usually normal. A baby who stays near the 15th percentile can be growing just as normally as one near the 85th.

My baby dropped from the 50th to the 25th percentile. Should I worry?

Moving one line is common, the NHS says, and a dip during illness usually recovers within 2 to 3 weeks. Crossing two centile lines is less common and worth raising with your polyclinic nurse.

Which growth charts does Singapore use?

The Child Health Booklet and HealthHub's e-service use Singapore's local growth charts. Many online calculators, including ours, use the WHO Child Growth Standards, so the numbers can differ slightly.

What does growth percentile mean on the HealthHub app?

HealthHub says it shows how your child's measurement compares with others in the same age group. At the 75th percentile, your child is as big as or bigger than 75% of them.

Related terms

• Health Booklet: The Child Health Booklet every Singapore baby gets at delivery. It records growth, milestones and every vaccination.
• Polyclinic: A public primary care clinic with subsidised fees, where Singapore families can take children for jabs and checks.
• Low Birth Weight: A birth weight under 2.5 kg, from being born early, growing slowly in the womb, or both.
• Preterm (Premature) Birth: A baby born alive before 37 completed weeks of pregnancy. In Singapore, about 8.5% of babies arrive this early.
• Fontanelle (Soft Spot): A soft, membrane-covered gap between a baby's skull bones. The one on top usually closes by 12 to 18 months.

See every term in the glossary