Length for girls at 10 months

At 10 months, the median length for girls on the WHO Child Growth Standards is 71.5 cm (28.1 in): half of girls this age measure less and half more. The middle half of girls, from the 25th to the 75th percentile, falls between 69.8 and 73.1 cm, a spread of 3.3 cm. The outer lines of the chart, the 2nd and 98th percentiles, sit at 66.5 and 76.4 cm.

Since 9 months, the median has risen by 1.3 cm in one month. By 11 months it reaches 72.8 cm. That monthly change is less than half the 4.5 cm of the first month, because growth slows steadily through the first two years.

For boys at 10 months the median is 73.3 cm, 1.8 cm more than for girls, which is why the charts are drawn separately by sex.

On the older CDC 2000 infant charts, which some clinics and websites still use before age 2, the median at 10 months is 71.3 cm. A girl exactly on the WHO median would read as about the 53rd percentile there, one reason two charts can give different answers for the same length.

Reading the table: a girl at 10 months who measures 72.5 cm is at about the 66th percentile, meaning that out of 100 girls this age, about 66 measure less. Under 2, this is length measured lying down. If a child under 2 was measured standing, WHO adds 0.7 cm before comparing.