Head Circumference Chart: Normal Head Size for Baby Boys and Girls (WHO)

The average (median) head circumference at birth is 34.5 cm for boys and 33.9 cm for girls (WHO). By 12 months it is 46.1 cm for boys and 44.9 cm for girls. The full month-by-month charts are below — boys first, then girls.

Source: WHO Child Growth Standards (2006), Head circumference-for-age, birth to 5 years, percentiles — boys and girls tables, World Health Organization. https://www.who.int/tools/child-growth-standards/standards/head-circumference-for-age

Values below are transcribed from the official WHO percentile tables. Note: the 3rd percentile is close to, but not the same as, −2 SD — the cut-off doctors actually use. Your pediatrician calculates the exact figure; do not diagnose from this table.

Head Circumference Chart for Boys (0–24 months)

Age	3rd percentile	50th percentile (median)	97th percentile
Birth	32.1	34.5	36.9
1 mo	35.1	37.3	39.5
2 mo	36.9	39.1	41.3
3 mo	38.3	40.5	42.7
4 mo	39.4	41.6	43.9
5 mo	40.3	42.6	44.8
6 mo	41.0	43.3	45.6
7 mo	41.7	44.0	46.3
8 mo	42.2	44.5	46.9
9 mo	42.6	45.0	47.4
10 mo	43.0	45.4	47.8
11 mo	43.4	45.8	48.2
12 mo	43.6	46.1	48.5
13 mo	43.9	46.3	48.8
14 mo	44.1	46.6	49.0
15 mo	44.3	46.8	49.3
16 mo	44.5	47.0	49.5
17 mo	44.7	47.2	49.7
18 mo	44.9	47.4	49.9
19 mo	45.0	47.5	50.0
20 mo	45.2	47.7	50.2
21 mo	45.3	47.8	50.4
22 mo	45.4	48.0	50.5
23 mo	45.6	48.1	50.7
24 mo	45.7	48.3	50.8

Head Circumference Chart for Girls (0–24 months)

Age	3rd percentile	50th percentile (median)	97th percentile
Birth	31.7	33.9	36.1
1 mo	34.3	36.5	38.8
2 mo	36.0	38.3	40.5
3 mo	37.2	39.5	41.9
4 mo	38.2	40.6	43.0
5 mo	39.0	41.5	43.9
6 mo	39.7	42.2	44.6
7 mo	40.4	42.8	45.3
8 mo	40.9	43.4	45.9
9 mo	41.3	43.8	46.3
10 mo	41.7	44.2	46.8
11 mo	42.0	44.6	47.1
12 mo	42.3	44.9	47.5
13 mo	42.6	45.2	47.7
14 mo	42.9	45.4	48.0
15 mo	43.1	45.7	48.2
16 mo	43.3	45.9	48.5
17 mo	43.5	46.1	48.7
18 mo	43.6	46.2	48.8
19 mo	43.8	46.4	49.0
20 mo	44.0	46.6	49.2
21 mo	44.1	46.7	49.4
22 mo	44.3	46.9	49.5
23 mo	44.4	47.0	49.7
24 mo	44.6	47.2	49.8

Head Circumference Chart 2–5 Years (Boys & Girls)

Age	Boys 3rd pct	Boys 50th pct	Boys 97th pct	Girls 3rd pct	Girls 50th pct	Girls 97th pct
3 yr (36 mo)	46.8	49.5	52.1	45.9	48.5	51.2
4 yr (48 mo)	47.5	50.2	53.0	46.7	49.3	52.0
5 yr (60 mo)	47.9	50.7	53.5	47.2	49.9	52.6

Boys’ heads run about 0.5–1.2 cm larger than girls’ at every age. Always read your baby’s number against the chart for their sex.

How to Measure Your Baby’s Head Circumference Correctly

Head circumference is measured at the widest point — around the forehead, above the eyebrows and ears, over the most prominent part of the back of the head (occipito-frontal circumference / OFC). Use a non-stretchable tape. Measure 3 times, take the largest. A cloth/stretched tape is the #1 cause of a false alarming number at home.

Premature babies must be plotted on corrected age, not birth age.

A head measured in the first day or two of life can read low. Moulding from birth and caput (swelling) squeeze the head; it rounds out over the first week, so the 1-week measurement often looks like a sudden jump. That is normal.

What if My Baby’s Head Is Small? (Microcephaly)

Term	Definition	Chart equivalent
Microcephaly	Head circumference more than 2 SD below the mean for age and sex	Roughly at or below the 3rd-percentile line above. The exact cut-off is −2 SD, which your pediatrician calculates — it is very close to, but not identical with, the 3rd percentile.
Severe microcephaly	More than 3 SD below the mean	Well below the 3rd percentile

• A single measurement below the 3rd percentile is not a diagnosis. Roughly 3 in 100 perfectly healthy babies sit below the 3rd percentile, purely by definition.
• The trend matters more than any one point. A baby tracking steadily along the 5th percentile is usually fine. A baby who crosses down from the 50th to the 5th is not.
• Head circumference below the 3rd percentile plus developmental delay, poor feeding, or not meeting milestones should be checked by a paediatrician.

What if My Baby’s Head Is Large? (Macrocephaly)

Term	Definition	Chart equivalent
Macrocephaly	Head circumference more than 2 SD above the mean for age and sex	Above the 97th percentile (the right column)

• A single measurement above the 97th percentile is not a diagnosis. Roughly 3 in 100 perfectly healthy babies sit above the 97th percentile, purely by definition. Many big-headed babies simply have big-headed parents (benign familial macrocephaly) — the paediatrician will often measure the parents’ heads.
• The trend matters more than any one point. A baby who crosses up from the 50th to above the 97th over successive visits needs review.

Red Flags — When to See a Doctor

• Head circumference crossing percentile lines in either direction (e.g. from the 50th down to the 10th, or up from the 50th to above the 97th) over successive visits
• Rapidly increasing head size / head growing much faster than length and weight
• Bulging, tense or firm fontanelle (soft spot) when the baby is calm and upright — possible raised intracranial pressure / hydrocephalus
• Sunset eyes (eyes fixed downward), prominent scalp veins, rapidly enlarging head, persistent vomiting, high-pitched cry, seizures — emergency
• Fontanelle that is sunken (dehydration) or that closes very early
• Head circumference below the 3rd percentile plus developmental delay, poor feeding, or not meeting milestones
• Any measurement below the 3rd or above the 97th percentile — get it confirmed by a paediatrician; do not self-diagnose from a home tape measure

🚨 Seek emergency care the same day if your baby has a bulging or very full fontanelle together with repeated vomiting, unusual drowsiness or being hard to wake, a high-pitched cry, seizures, or a rapidly enlarging head — these can signal raised pressure inside the skull. Call 112 (national emergency) or 108 (ambulance), or go to the nearest hospital.

Which Chart Should Indian Parents Use — WHO or IAP?

For children under 5 years, the WHO Child Growth Standards are the correct chart to use in India. The Indian Academy of Pediatrics (IAP) endorses the WHO 2006 standards for the 0–5 year age group, and this is what India’s national growth-monitoring (including the Mother and Child Protection Card) uses. The WHO standards are prescriptive — they describe how children should grow under optimal nutrition, and the WHO Multicentre Growth Reference Study that produced them included an Indian site (Delhi), which is one reason they are considered applicable to Indian children.

IAP’s own growth charts (revised 2015) cover 5–18 years, and are for height, weight and BMI only — they do not include head circumference. So there is no “IAP head circumference chart” for babies: for head circumference in the under-5s, WHO is the standard, in India and everywhere.

Frequently Asked Questions

Q: My baby’s head circumference is in the 95th percentile — should I be worried?

A: Not necessarily. Being in the 95th percentile simply means your baby’s head is larger than 95% of babies the same age. If your baby has always been around this percentile and is meeting developmental milestones, this is likely just their normal. Family history of larger heads also plays a role. Your pediatrician will monitor the growth pattern, not just one measurement.

Q: My baby’s head is below the 3rd percentile — does that mean microcephaly?

A: Not on its own. A single reading below the 3rd percentile is not a diagnosis — about 3 in 100 healthy babies sit below it by definition. What matters is the trend over time and whether your baby is feeding well and meeting milestones. Have it confirmed by your pediatrician with a proper non-stretchable tape rather than self-diagnosing from a home measurement.

Q: When does the soft spot (fontanelle) close?

A: The front soft spot typically closes between 9-18 months, while the smaller back one usually closes by 2-3 months. The soft spot allows for brain growth and is protected by a tough membrane, so gentle touching and cleaning during normal care is fine. Do contact your pediatrician if the soft spot is persistently bulging, very sunken, or closes much earlier or later than expected.

Q: How often should head circumference be measured?

A: Your pediatrician will measure at every well-baby visit - typically at birth, 1 week, 1 month, 2 months, 4 months, 6 months, 9 months, 12 months, 15 months, 18 months, and 24 months. After age 2, measurements are less frequent unless there are concerns.

---

This is general information and not a substitute for advice from your pediatrician. In an emergency, call 112 or 108.

---

Related Tools

• Baby Growth Chart

Q: Mera baby ka sir bada lag raha hai - is this normal?

A: In most cases, yes! Many Indian babies have heads that appear larger in proportion to their bodies - this is often genetic and usually nothing to worry about. What matters is that your baby’s head is growing at a consistent rate on their growth chart. If it’s following the same percentile curve, there’s usually nothing to worry about.

Q: Will my baby’s head shape become normal? It looks a bit flat on one side.

A: Positional flattening (plagiocephaly) is very common and usually improves as babies start sitting up and spending less time on their backs. Tummy time, repositioning, and sometimes a special helmet can help in more noticeable cases. Most babies’ heads round out beautifully by age 1-2.