Fill in the details and click Calculate to see your results.
This calculator is also in our free app. Sign in with the same account to keep your history in sync.
Head circumference (also called OFC, occipitofrontal circumference) tracks brain growth. It grows fastest in the first year — about 12 cm — and doctors measure it at every check-up until age 2–3.
Enter the measurement and date of birth to see the percentile. Values below the 3rd or above the 97th percentile, or a head that crosses percentile lines quickly, should be reviewed by your doctor.
| Sex | Boy |
| Date of Birth | 15 Jan 2026 |
| Date Measured | 15 Jan 2026 |
| Head Circumference | 34.5 |
| Length Unit | cm |
| Growth chart / country | WHO — India, UK, Australia & most countries |
| Born at (weeks of pregnancy) | 40 weeks |
| Head circumference percentile | 51st percentile |
| What it means | Out of 100 boys of the same age, about 51 have a lower head circumference and 49 a higher one. |
| Assessment | Within the normal range |
| Z-score (SD score) | 0.03 |
| Median (50th percentile) for this age | 34.46 cm |
| Normal range (3rd–97th percentile) | 32.07 – 36.85 cm |
| Age used | 0 weeks 0 days |
| Growth chart | WHO (international — used in India, UK, Australia and most countries) |
51st percentile.
Try this example →| Sex | Girl |
| Date of Birth | 15 Jul 2025 |
| Date Measured | 15 Jan 2026 |
| Head Circumference | 42 |
| Length Unit | cm |
| Growth chart / country | WHO — India, UK, Australia & most countries |
| Born at (weeks of pregnancy) | 40 weeks |
| Head circumference percentile | 43rd percentile |
| What it means | Out of 100 girls of the same age, about 43 have a lower head circumference and 57 a higher one. |
| Assessment | Within the normal range |
| Z-score (SD score) | -0.18 |
| Median (50th percentile) for this age | 42.23 cm |
| Normal range (3rd–97th percentile) | 39.78 – 44.68 cm |
| Age used | 6 months 1 day |
| Growth chart | WHO (international — used in India, UK, Australia and most countries) |
43rd percentile.
Try this example →It compares your child with 100 children of the same age and sex. The 60th percentile means your child measures more than 60 of them and less than 40.
No. Any percentile between about the 3rd and 97th can be healthy. What matters is that your child grows steadily along roughly the same curve.
About 34–35 cm on average; the normal range is roughly 32–37 cm.
Often yes: large heads frequently run in families (benign familial macrocephaly). Your doctor will check how fast it is growing and whether parents have large heads too.