WHO Growth Chart Calculator

What are WHO Growth Charts?

The WHO Growth Charts are international child growth standards developed by the World Health Organization to assess how children grow from birth through adolescence.

Unlike older national charts that simply describe how children did grow, the WHO standards describe how healthy, breastfed children from six diverse countries (Brazil, Ghana, India, Norway, Oman and the USA) actually should grow when nutrition and health care are optimal. That makes them the global reference for clinical pediatrics, public health surveillance and nutrition programs.

Age groups

• 0-5 years: WHO Child Growth Standards built from the Multicentre Growth Reference Study (MGRS), released in 2006. These are the gold-standard charts for infants and young children.
• 5-19 years: WHO Growth Reference for school-age children and adolescents, reconstructed in 2007 from the 1977 NCHS/WHO reference to align with the under-5 standards at age 5.

Why growth charts matter

Growth charts help clinicians and parents:

• Track a child's growth trajectory over time, not just a single point
• Spot stunting, wasting, overweight and obesity early enough to act
• Assess nutritional status independent of country-specific norms
• Measure the impact of health, feeding and disease interventions
• Compare growth fairly across different populations and care settings

What is a healthy Z-score range for my child?

A Z-score between -2 and +2 covers about 95 percent of healthy children and is considered the normal range. Z-scores from -3 to -2 indicate moderate stunting or underweight; below -3 is severe and warrants medical follow-up. Above +2 the picture is more nuanced: for height it just means tall (often genetic), but for weight-for-age it can indicate overweight, and for weight-for-height it points to obesity. A single Z-score is a snapshot - your child's trajectory across visits is more important than any single number.

Should I use the WHO chart or the CDC growth chart?

For children under 2 years, WHO is the global recommendation - the CDC itself adopted the WHO standards for this age group in 2010. The WHO standards describe how healthy breastfed children grow, while older CDC charts describe how (mostly formula-fed) American children grew in the 1970s. For children 2-19 either WHO or CDC is acceptable; CDC is still used in the United States while WHO is used internationally. If you switch charts mid-childhood, expect a small step in percentile - the charts are calibrated to align at age 2 but are not identical.

My baby was born premature - does the chart still apply?

Yes, but use corrected age, not chronological age, for the first two to three years. Corrected age = chronological age minus the number of weeks born before 40 weeks. A baby born at 32 weeks who is now 8 months old should be plotted as 6 months on the WHO chart. Most clinicians correct until age 2 (or age 3 for very preterm under 28 weeks), then transition to chronological age. Without correction, every premature baby will look stunted on the chart, even when growing perfectly for their gestational stage.

My child dropped from the 75th to the 25th percentile - should I worry?

A single big shift in percentile is worth a pediatric review, especially in children under 2. Crossing two major percentile lines (75th, 50th, 25th, 10th) downward, or sudden flat growth, can signal feeding issues, chronic illness, food allergies, gut absorption problems or hormonal causes. That said, two minor exceptions are normal: between 6-18 months babies often shift percentiles as their genetic growth pattern takes over from birth weight, and adolescents shift around puberty. A child who is consistently on the same line is doing fine, even if that line is the 10th percentile - it is the consistency that matters.

What's the difference between weight-for-age, weight-for-height and BMI-for-age?

All three measure body composition but at different angles. Weight-for-age (used 0-10 years) tells you if a child is the expected weight for their birthday but does not separate skinny tall kids from heavy short kids. Weight-for-height (used 0-5 years) compares weight to how tall the child actually is, which catches under- or over-nutrition in stunted or fast-growing children. BMI-for-age (used 5-19 years) is the standard for school-age and adolescents and is the WHO-recommended metric for overweight and obesity screening in older children. Pediatricians usually look at all three when assessing nutrition status.

Are tall and short percentiles really hereditary?

Largely yes. Mid-parental height (the average of both parents' heights, plus 6.5 cm for boys or minus 6.5 cm for girls) predicts a child's adult height within about 5 cm for most healthy children. A child consistently on the 10th percentile with two short parents is genetically on track and does not need treatment. A child whose growth velocity drops below the third percentile or who clearly falls off their genetic trajectory should be evaluated for growth hormone deficiency, thyroid issues, celiac disease, kidney disease or psychosocial factors. The chart flags concern; the family history and full work-up confirm or rule it out.

Why does my exclusively breastfed baby look like she's gaining weight slowly on some charts?

Because some older charts (especially pre-2010 CDC) were built from formula-fed infants, who tend to gain weight faster than breastfed babies after 3-4 months. On those charts an exclusively breastfed baby may appear to be falling off her curve when she is in fact growing perfectly. The WHO standards specifically used breastfed infants as the reference, so they correctly represent normal breastfeeding growth patterns. If your pediatrician is comparing your breastfed baby against an old chart, asking them to re-plot her on the WHO chart is a reasonable request.

How often should a child's height and weight be plotted?

Standard pediatric schedules plot growth at every well-child visit: monthly until 6 months, every 2-3 months until age 1, then every 3-6 months until age 2, twice a year until age 5, and yearly until adolescence. A growth concern, illness or feeding problem may justify more frequent measurements. Single measurements are far less useful than a trajectory across visits, so consistent technique matters: same scale, same shoeless height measurement, ideally same time of day. Plotting yourself between visits is fine for awareness but should not replace the pediatrician's formal review.