Convert a baby's birth date into age in weeks, days and months.
The baby's age in days is the calendar gap between the birth date and today, then broken into full weeks, leftover days and months. Parents quote weeks early on because development milestones are tracked that way. Infant milestones like feeding, sleep and growth are measured in weeks during the first year, so a quick date-to-weeks conversion answers a question parents ask constantly.
Baby Age in Weeks
Age in weeks = days since birth / 7 (full weeks) plus the leftover days
Age in weeks = days since birth / 7 (full weeks) plus the leftover days The baby's age in days is the calendar gap between the birth date and today, then broken into full weeks, leftover days and months. Parents quote weeks early on because development milestones are tracked that way.
Infant milestones like feeding, sleep and growth are measured in weeks during the first year, so a quick date-to-weeks conversion answers a question parents ask constantly.
This calculator takes 6 inputs: Birth year, Birth month, Birth day, Today's year, Today's month, Today's day. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.