What does height-for-age mean?

Height-for-age compares your child's height to the WHO reference population of the same age and sex. A height-for-age z-score below -2 (below the 3rd percentile) indicates stunting — a sign of chronic undernutrition or chronic illness that may require medical evaluation.

Should I use length or height for my baby?

Children under 2 years are measured lying down (recumbent length). Children 2 years and older are measured standing (height). Standing height is typically 0.5–1 cm less than recumbent length. WHO growth charts use length for children under 2 and height for those 2 and over.

At what percentile is my child considered short?

Below the 3rd percentile (z-score below -2) is the WHO threshold for 'stunting' or 'short stature' that warrants medical evaluation. However, a child who has consistently been at the 5th percentile and is following their growth curve is usually healthy — it's the trend that matters most.

Child Height Percentile Calculator — WHO Standards

Length vs Height — Which Should I Use?

Children under 2 are measured lying down (recumbent length). Children 2 and over are measured standing up (height). This matters because standing height is approximately 0.5–1 cm shorter than recumbent length. WHO growth charts are calibrated accordingly — this calculator uses the correct reference for each age range automatically.

Understanding Stunting vs Short Stature

The WHO uses height-for-age as a key indicator of chronic nutritional status and overall health:

Z-Score	Percentile	Classification
< −3	< 0.1st	Severe stunting
−3 to −2	0.1–2.3rd	Stunted (chronic undernutrition)
−2 to +2	2.3–97.7th	Normal range
> +2	> 97.7th	Tall (usually not a concern)

Stunting (height-for-age z-score below −2) reflects chronic undernutrition or illness and requires pediatric evaluation. Wasting (weight-for-height below −2) reflects acute undernutrition. Both are distinct and require different interventions.

Average Heights by Age (WHO Medians)

Age	Boys (cm)	Girls (cm)
Birth (0 months)	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	80.8
24 months	87.8	86.4
36 months	96.1	94.4
48 months	102.9	100.8
60 months	109.2	106.7

Frequently Asked Questions

What is the average height for a 1-year-old?

According to WHO growth standards, the median height for a 12-month-old boy is approximately 75.7 cm (29.8 in) and for a girl is approximately 74.0 cm (29.1 in). Healthy children at this age range from roughly 69–83 cm.

What does a height-for-age z-score of −1 mean?

A z-score of −1 corresponds to approximately the 16th percentile. This is well within the normal range (3rd–97th percentile). Your child is slightly shorter than the WHO median but completely healthy. No action is needed unless the trend is dropping.

Can I use this calculator for children over 5 years?

This calculator is validated for ages 0–60 months using the WHO 2006 growth standards. For children 5–19 years, WHO uses a separate reference (2007). GrowChart's full app tracks all ages using the appropriate standard automatically.

Should I use corrected age for my premature baby?

Yes — for height as well as weight. Use corrected age (chronological age minus weeks premature) until your child is 2 years old. Our Corrected Age Calculator makes this easy.

Track height across every visit

GrowChart plots your child's full growth trajectory on WHO percentile charts, automatically flags concerning trends, and generates PDF reports for your pediatrician.

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Child Height & Length Percentile Calculator

Length vs Height — Which Should I Use?

Understanding Stunting vs Short Stature

Average Heights by Age (WHO Medians)

Frequently Asked Questions

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Track height across every visit