The WHO growth charts for girls aged 5 to 19 track two main measurements: height-for-age and BMI-for-age. These charts, known as the WHO Reference 2007, are the international standard used to assess whether a school-age girl is growing as expected compared to a healthy reference population. You can access them for free on the WHO website as downloadable PDFs or through interactive tools.
What the Charts Measure
For girls in this age range, the WHO provides two core indicators. Height-for-age shows whether a girl’s stature is on track relative to her peers. BMI-for-age combines weight and height into a single number that reflects whether body proportion is healthy. Together, these two charts give a clearer picture than weight alone.
Weight-for-age charts are only available up to age 10 for this reference set. The WHO intentionally stops tracking weight by itself after that point because puberty changes the picture. During the growth spurt, a girl who is simply tall can look overweight on a weight-for-age chart even though her body composition is perfectly normal. BMI-for-age solves this by accounting for height, making it the preferred tool from age 10 onward.
How the Charts Are Built
The WHO Reference 2007 is a reconstruction of the original 1977 NCHS/WHO reference data, updated using modern statistical methods. For children under five, the WHO created strict growth “standards” in 2006 based on a carefully selected group of healthy, breastfed children from six countries. The 5-to-19 charts were designed to align seamlessly with those younger-child standards at age five, creating a smooth transition from one set of charts to the next.
This matters because the WHO charts represent how children should grow under good conditions, not just how they happened to grow in one country during one time period. That’s a key difference from the CDC growth charts, which describe how U.S. children actually grew between 1963 and 1994. The CDC charts are a reference (a snapshot of a population), while the WHO approach aims closer to a universal benchmark.
Reading the Lines on the Chart
Each WHO chart shows a set of curved lines representing standard deviations (SD) from the median. The middle line is the median, or 50th percentile. Lines above and below it are labeled +1SD, +2SD, +3SD, and their negative counterparts. When you plot a girl’s measurement on the chart, her dot falls between or on these lines, telling you how she compares to the reference population.
The WHO uses the +2SD and -2SD lines as the main cutoffs for flagging potential concerns. These correspond roughly to the 2.3rd and 97.7th percentiles. In practical terms:
- Within -2SD to +2SD: Normal range for the vast majority of healthy girls.
- Below -2SD for height-for-age: Classified as stunted, meaning growth may be chronically restricted.
- Below -3SD for height-for-age: Severely stunted.
A single measurement is useful, but the real value comes from plotting several measurements over time. A girl who has always tracked along the 15th percentile is growing consistently. A girl who drops from the 50th to the 10th percentile over a year or two is showing a trend that needs attention, even if her current number still falls in the normal range.
BMI-for-Age Cutoffs for Girls
The BMI-for-age chart uses its own set of thresholds, and they shift with age because a healthy BMI changes as a girl grows. The WHO defines the categories this way:
- Overweight: BMI above +1SD. At age 19, this line aligns with a BMI of 25.
- Obese: BMI above +2SD. At age 19, this corresponds to a BMI of 30.
- Thin: BMI below -2SD.
- Severely thin: BMI below -3SD.
These cutoffs are designed to connect naturally with the adult BMI categories everyone is familiar with. A 19-year-old girl whose BMI crosses the +1SD line on the WHO chart lands right at BMI 25, which is the standard adult threshold for overweight. This continuity makes the transition from pediatric to adult monitoring straightforward.
For younger girls, the absolute BMI numbers that correspond to each line are lower. A 7-year-old with a BMI of 18 is already above the +1SD line, while the same BMI at age 14 sits comfortably in the normal range. This is exactly why age-specific charts exist: a raw BMI number means nothing for children without the context of age and sex.
How to Plot a Measurement
To use the chart, you need the girl’s exact age in years and months, along with the measurement you’re plotting (height in centimeters, or BMI calculated from height and weight). Find her age along the horizontal axis, find the measurement on the vertical axis, and mark where the two lines meet. The dot’s position relative to the curved SD lines tells you her percentile range.
Calculating BMI requires dividing weight in kilograms by height in meters squared. For a girl who is 140 cm tall and weighs 35 kg, that’s 35 ÷ (1.40 × 1.40) = 17.9. You’d plot 17.9 on the vertical axis against her age on the horizontal axis. Many online calculators and pediatric software do this automatically.
Why the WHO Charts Differ From CDC Charts
If you’ve seen growth charts at a U.S. pediatrician’s office, those were likely CDC charts. The two systems overlap in purpose but differ in philosophy and data. The CDC charts reflect how American children grew across several national surveys from the 1960s through the 1990s. That population included children with a wide range of feeding practices: only about half were ever breastfed, and just a third were still breastfeeding at three months.
The WHO sample was far more selective. It excluded premature babies, multiple births, children born at high altitude, and those whose mothers smoked. Every child in the study was breastfed for at least 12 months and introduced to solid foods between four and six months. The result is a reference that represents growth under favorable conditions rather than average conditions in any single country.
For most girls aged 5 to 19, the practical differences between the two chart systems are small. But the WHO charts tend to classify slightly more children as overweight and slightly fewer as underweight compared to CDC charts, because the reference population was leaner. Many countries outside the United States use the WHO charts as their default, and the WHO recommends them for international comparisons.
The Puberty Factor
Girls typically experience their peak growth spurt earlier than boys, often between ages 10 and 13. During this window, it’s common for height to increase by 7 to 12 cm in a single year. The WHO charts account for this by widening the normal range during puberty. The spread between the outer SD lines gets larger in the adolescent years, reflecting the natural variation in when puberty starts and how quickly growth progresses.
A girl who starts puberty early may temporarily jump to a higher percentile on the height chart, while a late bloomer might appear to fall behind. Neither pattern is necessarily a problem. What matters most is whether the overall trajectory is smooth and consistent. Sudden jumps or drops across two or more SD lines over a short period are the patterns worth investigating, not where a girl sits at any single point in time.