AT BIRTH · KG
Average newborn weight and weight percentiles
Birth measurements are a starting point. This table is for day zero; early infancy changes quickly, so use the exact measurement date for later readings.
Average newborn weight at birth
In the WHO reference, the median birth weight is 3.23 kg for girls and 3.35 kg for boys. People often say “average newborn weight”; this page uses the WHO median, the middle of the reference distribution.
Average, median and percentile are not the same
A population average is calculated from recorded births. The WHO 50th percentile is the middle of a growth-standard distribution. This page reports the WHO median so it stays consistent with the calculator; it does not claim that value is the current average for every country or gestational age.
Gestational age matters. The full-term WHO comparison shown here is not a preterm growth assessment and does not correct age for an early birth.
Continue from the birth measurement
Weight reference at 0 days
Values below are in kg. The columns are reference percentiles, not recommended limits. This table uses the day-of-birth reference.
| WHO reference | 3rd | 25th | 50th | 75th | 97th |
|---|---|---|---|---|---|
| Girls | 2.44 | 2.93 | 3.23 | 3.55 | 4.17 |
| Boys | 2.51 | 3.03 | 3.35 | 3.69 | 4.35 |
How to use this table
Find the row for the sex used in your baby’s growth record, then compare the measurement in kg. Between two columns means between those reference percentiles. The calculator gives a more precise comparison using daily WHO parameters.
Measure weight consistently
Use a baby scale on a stable, level surface. Record the measurement and date as accurately as possible, and keep clothing and weighing conditions consistent between visits.
What this comparison cannot tell you
A weight percentile alone cannot tell you whether a baby is underweight or overweight. Length, feeding, medical history and the pattern over time also matter. The number does not diagnose a condition or establish a growth goal.
Read the weight percentile guide or browse other ages and measurements.
Source: WHO Child Growth Standards, expanded daily tables. Values derived with the LMS method and rounded to two decimals. Methodology and limitations.
WORKED EXAMPLE
Birth weight versus a later weight
A 3.23 kg girl at birth is at the WHO median shown in this page’s table. If she is weighed again several days later, that measurement needs its own date and daily reference; it should not be compared with the day-zero row.
Which newborn number is this?
| Term | Meaning | Use here |
|---|---|---|
| Birth weight | The measurement taken at or just after birth. | Compare with the day-zero table. |
| Later newborn weight | A measurement on a later date. | Use exact dates in the calculator. |
| WHO median | The reference distribution midpoint. | Do not treat it as an individual target. |
Newborn weighing checklist
- Use a calibrated infant scale on a stable surface.
- Keep clothing and diaper conditions consistent when comparing readings.
- Record the date and time; do not label a later reading as birth weight.
Questions parents ask
Is the WHO median the same as the average birth weight in my country?
No. It is the middle of the WHO growth-standard distribution, not a current national birth statistic.
Does this table apply to premature babies?
It is a full-term WHO reference and does not correct for gestational age. Ask a healthcare professional which chart to use.
Why use the exact day after birth?
Weight can change quickly after birth. Day zero values should not be reused for measurements taken later.
Review status: Maintained by Baby Growth and technically reviewed on 29 September 2026. Calculations and product ranges are checked against the cited WHO, CDC and manufacturer sources. This independent tool has not received clinical review and does not replace professional care.