Where does a birth weight sit?
Birth weight has clinical cut-offs rather than a simple average. Here they are on one scale.
Typical
3.3 kg — closest reference: global average at 3.3 kg.
Reference figures are measurements and are rounded; the unit conversion behind them is exact.
| Reference | Size | Yours ÷ theirs | Note |
|---|---|---|---|
| very low birth weight | 1.5 kg | 2.2× | |
| low birth weight | 2.5 kg | 1.32× | |
| global average | 3.3 kg | 1× | |
| large for dates | 4 kg | 0.825× | |
| heaviest recorded | 10.2 kg | 0.324× | Italy, 1955 |
Worth knowing
- The average newborn weighs about 3.3 kg, but the healthy range runs from 2.5 to 4.0 kg — a spread of 60%.
- Babies typically lose 5–10% of their birth weight in the first days and regain it within two weeks.
Frequently asked
What counts as a low birth weight?
Below 2 500 g, regardless of gestational age. Below 1 500 g is very low and below 1 000 g extremely low. The thresholds are WHO definitions used worldwide.
Is a big baby a problem?
Above 4 000 g (macrosomia) raises the risk of a difficult delivery, and above 4 500 g more so. It is a flag for extra monitoring rather than a diagnosis.
How to read this
These are population thresholds, not medical advice. A clinician interprets birth weight alongside gestational age.
Where the numbers come from
- WHO definitions of low birth weight