A baby growth chart shows how a baby’s weight and length change as they get older, and how those measurements compare with other babies of the same age and sex. This baby growth chart uses the World Health Organization (WHO) Child Growth Standards, which are the reference pediatricians around the world use to follow healthy growth from birth to 24 months.
Parents use a baby growth chart to see whether their baby is growing steadily between check-ups, and pediatricians plot each new measurement on the chart at every visit. A single measurement matters far less than the pattern over time: a baby who follows their own curve, feeding well and staying alert, is usually growing exactly as they should.
Baby weight chart (median weight, kg)
The table below shows the median (50th percentile) weight for boys and girls from birth to 24 months, according to the WHO standards. A baby on the 50th percentile weighs the same as or more than half of babies their age and sex.
| Age | Boys | Girls |
|---|---|---|
| Birth | 3.3 | 3.2 |
| 3 months | 6.4 | 5.8 |
| 6 months | 7.9 | 7.3 |
| 9 months | 8.9 | 8.2 |
| 12 months | 9.6 | 8.9 |
| 18 months | 10.9 | 10.2 |
| 24 months | 12.2 | 11.5 |
Baby length chart (median length, cm)
This table shows the median (50th percentile) length for boys and girls over the same ages. Length is measured lying down for babies under 24 months.
| Age | Boys | Girls |
|---|---|---|
| Birth | 49.9 | 49.1 |
| 3 months | 61.4 | 59.8 |
| 6 months | 67.6 | 65.7 |
| 9 months | 72.0 | 70.1 |
| 12 months | 75.7 | 74.0 |
| 18 months | 82.3 | 80.7 |
| 24 months | 87.1 | 85.7 |
How to read a growth chart
A growth chart is made up of curved percentile lines. If a baby’s weight sits on the 25th percentile line, it means about 25 out of every 100 babies of the same age and sex weigh the same or less, and about 75 weigh more. The middle line is the 50th percentile, which is the median shown in the tables above.
Most healthy babies track somewhere between the 3rd and 97th percentile lines, so a low or high percentile on its own is not a cause for worry. What matters most is a steady curve: a baby who keeps following roughly the same percentile line over several months is growing consistently, even if that line is well above or below the middle. A sudden jump or drop across two or more lines is something to discuss at the next check-up.
Boys and girls have separate charts because boys tend to be slightly heavier and longer on average at the same age. Always compare a baby with the chart for their own sex, and remember that every baby has their own growth pattern influenced by birth weight, feeding and family build.
Check your baby’s exact percentile
Want your baby’s exact position, not just the median? Use our baby percentile calculator to check your baby’s exact weight and length percentile in seconds. You can also work out their precise age in weeks, months and days with our baby age calculator, or focus on length alone with our height percentile calculator.
Frequently asked questions
What is an average weight for a 6-month-old?
At 6 months, the WHO median weight is about 7.9 kg for boys and about 7.3 kg for girls. These figures are the 50th percentile, so half of healthy 6-month-olds weigh more and half weigh less.
How fast do babies grow in the first year?
Babies grow fastest in the first few months, often gaining around 150 to 200 grams a week early on. Growth then slows gradually: most babies double their birth weight by about 5 to 6 months and triple it by around their first birthday, while length increases by roughly 25 cm in the first year.
What percentile is a healthy baby?
There is no single healthy percentile. Most healthy babies track between the 3rd and 97th percentiles and follow a steady curve over time. A baby on the 10th percentile who keeps following that line is usually growing just as well as a baby on the 90th percentile.
Do breastfed and formula-fed babies grow differently on the chart?
They can grow at slightly different rates, especially after the first few months. The WHO charts are based on breastfed babies as the norm, because the standards were built from healthy breastfed infants growing in optimal conditions, so they are suitable for all babies.
Disclaimer: The values on this page are WHO median (50th percentile) reference values provided for general information only. They are not medical advice and do not replace the judgment of a healthcare professional. If you have any concern about your baby’s growth, please consult your pediatrician.