Age and growth
Gestational and corrected age
From gestation at birth and age in days: postmenstrual age, corrected age and week of life.
For education. Check against your unit's guidance and a second clinician before use.
weeks
days
days
Fill in the boxes above to see the result.
How this is calculated
- Postmenstrual age = gestation at birth + chronological age.
- Corrected age (for babies born preterm) = postmenstrual age − 40 weeks, used to judge growth and development until about 2 years.
Sources
Checked by NICUlearn, 6 Oct 2026.