Child Growth Percentile Calculator

A growth percentile tells you how a child compares to a reference population of the same age and sex. A height at the 75th percentile means the child is taller than 75% of children their age. Percentiles between the 5th and 95th are generally considered within the typical range, but trends over time matter more than any single measurement.

Reference Standards

For children under 2 years, this tool uses the WHO 2006 Growth Standards, developed from a multicountry study of children raised in optimal conditions (breastfed, non-smoking households, etc.). Length is measured lying down.

For children 2 years and older, the tool switches to the CDC 2000 Growth Charts, which represent a cross-section of the U.S. population ages 2–20. Height is measured standing.

LMS Method

Percentiles are calculated using the LMS (Lambda-Mu-Sigma) method developed by Cole (1988). Each age has three parameters: L (Box-Cox power transformation to normalize the distribution), M (the median), and S (the coefficient of variation). The Z-score is calculated as:

Z = ((value/M)^L − 1) / (L × S)

The percentile is then the area under the standard normal curve to the left of Z.

Adult Height Prediction

The Khamis-Roche method (1994, Pediatrics 94:504–507) predicts adult stature from the child's current height, weight, and mid-parental height, for ages 4–17.5 years. The published standard error of estimate is approximately 2.1 inches (5.3 cm) for boys and 1.7 inches (4.3 cm) for girls.

The mid-parental height formula is a simpler estimate: boys = (mother + father + 13 cm) / 2; girls = (mother + father − 13 cm) / 2; with a typical range of ±8.5 cm.

BMI for Children

Unlike adult BMI, children's BMI is interpreted relative to age and sex. Categories follow CDC guidelines: below the 5th percentile = underweight; 5th–85th = healthy weight; 85th–95th = overweight; 95th and above = obese. BMI is not calculated for children under 2 years.

Data Sources

• WHO 2006 Child Growth Standards: de Onis M, et al. WHO Child Growth Standards. Geneva: WHO Press, 2006.
• CDC 2000 Growth Charts: Kuczmarski RJ, et al. Vital Health Statistics 11(246), 2002.
• Khamis-Roche adult height prediction: Khamis HJ, Roche AF. Pediatrics. 1994;94:504–507. (Erratum: 1995;95:457.)

Link to this tool with values filled in

Everything after the # stays in your browser — it is never sent to a server — so a link like this opens the tool ready to go without the values travelling anywhere but the address bar:

https://crunchify.net/tools/growth-percentile#dob=2022-03-14&sex=female&height=95&heightunit=cm&weight=14&weightunit=kg

Join the settings with &, and percent-encode each value so that spaces, newlines and any #, &, = or % inside one do not break the link. Leave a setting out to accept its default. If a setting is not recognised, the page says so rather than quietly ignoring it.

• sex (also gender) — male or female, defaults to male. Which reference chart to read. WHO and CDC publish separate tables and there is no combined one.
• dob (also birthdate,bornorbirthday) — text, up to 10 characters. The child’s date of birth as YYYY-MM-DD. Give this or `agemonths`, not both — this one wins.
• agemonths (also ageormonths) — a whole number from 0 to 240. Age in months, 0 to 240. An alternative to `dob` when the birth date is not to hand.
• height (also lengthorstature) — a whole number from 0 to 250. The child’s height or length, in the unit named below.
• heightunit (also heightunits) — cm or in, defaults to cm. Whether the height above is centimetres or inches. Never inferred from the number.
• weight (also mass) — a whole number from 0 to 200. The child’s weight, in the unit named below.
• weightunit (also weightunits) — kg or lbs, defaults to kg. Whether the weight above is kilograms or pounds. Never inferred from the number.
• head (also headcircorheadcircumference) — a whole number from 0 to 80. Head circumference in centimetres. Charted only under 5 years.

The tool reads these on arrival but never writes them back, so what you type here stays out of your browser history.